An Illustrated Synoptic Key and Comparative Morphology of the Larvae of Dryophthorinae (Coleoptera, Curculionidae) Genera with Emphasis on the Mouthparts

Abstract

This study provides an illustrated synoptic key and comparative morphology to the 38 known larvae of dryophthorine genera representing seven subtribes in four of the five tribes: Cactophagus LeConte, Cosmopolites Chevrolat, Cyrtotrachelus Schoenherr, Diathetes Pascoe, Diocalandra Faust, Dryophthoroides Roelofs, Dryophthorus Germar, Dynamis Chevrolat, Eucalandra Faust, Eugnoristus Schoenherr, Foveolus Vaurie, Mesocordylus Lacordaire, Metamasius Horn, Metamasius (=Paramasius Kuschel), Myocalandra Faust, Nassophasis Waterhouse, Nephius Pascoe, Odoiporus Chevrolat, Phacecorynes Schoenherr, Polytus Faust, Poteriophorus Schoenherr, Rhabdoscelus Marshall, Rhinostomus Rafinesque, Rhodobaenus LeConte, Rhynchophorus Herbst, Scyphophorus Schoenherr, Sipalinus Marshall, Sitophilus Schoenherr, Sparganobasis Marshall, Sphenophorus Schoenherr, Stenommatus Wollaston, Temnoschoita Chevrolat, Trigonotarsus Guerin-Meneville, Trochorhopalus Kirsch, Tryphetus Faust, Xerodermus Lacordaire, and Yuccaborus LeConte. Only Prodioctes Pascoe was not included due to lack of specimens to examine. Seven genera are reported here for the first time. Detailed line drawings of the mouthparts of 37 genera are provided. The synoptic key is a multi-entry key, different from a traditional, single entry dichotomous key, which allows the user to identify dryophthorine larvae using any combination of characters (couplets). A total of 52 characters are included. This study provides support for the retention of Stromboscerini in the subfamily.

1. Introduction

Some of the most devastating weevil pests that have plagued human agriculture globally have been dryophthorines (e.g., granary weevil (Sitophilus granarius (Linnaeus)) and palm weevils (Rhynchophorus ferrugineus (Olivier), R. vulneratus (Panzer), and R. palmarum Linnaeus)). Dryophthorines are major pests of various important agricultural commodities such as banana (e.g., Cosmopolites sordidus (Germar), Odoiporus longicollis (Olivier), and Polytus mellerborgii (Boheman)), agave (the sisal weevil Scyphophorus acupunctatus Gyllenhal), coconut palm (Rhinostomus barbirostris (Fabricius), Rhabdoscelus obscurus (Boisduval), and R. palmarum), sugar cane (Metamasius hemipterus (Linnaeus) and Rhabdoscelus obscurus), oil and sago palm (Rhabdoscleus obscurus, Rhynchophorus palmarum and R. ferrugineus), and date palm (Rhynchophorus palmarum) among other monocotyledons.

Worldwide, Dryophthorinae include approximately 1200 species in 153 genera and five tribes (Cryptodermatini, Dryophthorini, Orthognathini, Rhynchophorini and Stromboscerini;) with most species associated with woody monocots [1,2]. Cryptodermatini include the Oriental genus Cryptoderma Ritsema; Dryophthorini include the cosmopolitan Dryophthorus Germar and Stenommatus Wollaston and the Oriental/Australasian Psilodryophthorus Wollaston. Orthognathini are subdivided into two subtribes, Rhinostomina, which include Rhinostomus Rafinesque and Yuccaborus LeConte, and Orthognathina containing Mesocordylus Lacordaire, Orthognathus Schoenherr, and Sipalinus Marshall. The two most diverse tribes are Stromboscerini with 12 genera and Rhynchophorini, which include 125 genera in six subtribes [3].

The monophyly of Dryophthorinae has been supported by a number of higher-level phylogenic studies of the Curculionoidea [4,5,6]. However, the molecular-based phylogeny presented by McKenna et al. [7], which includes a taxon sampling of nine dryophthorines, does not recover a monophyletic Stromboscerini + Dryophthorinae. The phylogeny of Dryophthorinae is currently under study based on combined analyses of molecular and morphological data. The current comparative study of the morphological features of the immature stages, here presented in the form of a synoptic key, will serve as a valuable source of data towards inferring the phylogeny of the subfamily.

In an attempt to provide flexibility and usability of diagnostic tools, and circumvent the inherent limitations of single entry keys, a synoptic key structure is here adopted to provide the user with multiple start options when attempting to identify larval dryophthorines. In addition, an updated and overarching tool to identify Dryophthorinae larvae is sorely needed given the agricultural importance of this group and the limitations of currently available diagnostic tools [8]. Presently, to attempt an identification of dryophthorine larvae, a combination of several publications must be consulted, of which Anderson’s [9] and May’s [10] work stand out. Anderson’s [9] dichotomous keys work best with a perfectly preserved, prepared, and mounted specimen, which may not always be available. These keys also do not allow for the potential use of obvious characters of the head, thorax, and abdomen as a primary way to quickly eliminate distinct taxa. All currently known larvae representing 37 dryophthorine genera, with the exception of Prodioctes Pascoe (known as the rhizome weevil in India) are included in this key and incorporates seven (eight if Paramasius is granted generic status) new ones (Table 1). Three genera, Dynamis Chevrolat, Dryophthoroides Roelofs, and Xerodermus Lacordaire, were coded based on published records [11,12,13]. Detailed line drawings of the mouthparts of 37 genera, including reproductions of Gardner’s [11,12] illustrations of Dryophthoroides and Xerodermus, are provided in alphabetical order at the end of the key (Figure 56, Figure 57, Figure 58, Figure 59, Figure 60, Figure 61, Figure 62, Figure 63, Figure 64, Figure 65, Figure 66, Figure 67, Figure 68, Figure 69, Figure 70, Figure 71, Figure 72, Figure 73, Figure 74, Figure 75, Figure 76, Figure 77, Figure 78, Figure 79, Figure 80, Figure 81, Figure 82, Figure 83, Figure 84, Figure 85, Figure 86, Figure 87, Figure 88, Figure 89, Figure 90, Figure 91 and Figure 92).

Table 1. Genera of known dryophthorinae larvae arranged based on current classification, biogeographic range, and depository (Australian National Insect Collection, ANIC; British Museum of Natural History, BMNH; Instituto Nacional de Pesquisas de Amazonias, INPA; Museu Zoologico de Sao Paulo, MZSP; National Taiwan Normal University, Taipei, NTNU; United States National Museum, USNM). Paramasius Kuschel is here included as a separate genus from Metamasius Horn; however, this was done in an attempt to uncover potential characters that may distinguish this once valid genus from Metamasius. This table references the figure plates of each genus.

Dryophthorinae	Tribe	Subtribe	Figure	Genus (Described)	Genus (Previously Undescribed)	Region	Depository/Source
	Orthognathini	Rhinostomina	77	Rhinostomus Rafinesque		Circumtropical	USNM
			92	Yuccaborus LeConte		New World	USNM
		Orthognathina	3, 6, 66		Mesocordylus Lacordaire	Neotropical	USNM
			4, 81, 94	Sipalinus Marshall		Oriental	NTNU, USNM
	Rhynchophorini	Rhynchophorina	4, 7, 58	Cyrtotrachelus Schoenherr		Oriental	USNM
				Dynamis Chevrolat		Neotropical	[13]
			7, 11, 79	Rhynchophorus Herbst		Circumtropical	USNM
		Polytina	7, 74	Polytus Faust		Cosmopolitan	USNM
		Sphenophorina	56	Cactophagus LeConte		New World	USNM
			3, 7, 11, 57	Cosmopolites Chevrolat		Cosmopolitan	USNM
			4, 6, 59	Diathetes Pascoe		Australasian	ANIC
			1, 7, 63	Eucalandra Faust		Neotropical	USNM
			3, 6, 65		Foveolus Vaurie	Neotropical	MZSP
			3, 11, 67	Metamasius Horn		New World	USNM
			3, 7, 69		Nassophasis Waterhouse	Oriental	BMNH, USNM
			3, 6, 71	Odoiporus Chevrolat		Oriental	USNM
			3, 6, 72		Paramasius Kuschel	Neotropical	INPA
			2, 6, 11, 73, 93	Phacecorynes Schoenherr		Afrotropical	USNM
			4, 7, 75		Poteriophorus Schoenherr	Oriental	USNM, NTNU
				Prodioctes Pascoe		Oriental	N/A
			76	Rhabdoscelus Marshall		Oriental	USNM
			7, 11, 78	Rhodobaenus LeConte		New World	USNM
			2, 80	Scyphophorus Schoenherr		New World	USNM
			4, 6, 83		Sparganobasis Marshall	Australasian	ANIC
			2, 7, 84, 85	Sphenophorus Schoenherr		Nearctic/Holarctic	USNM
			2, 87	Temnoschoita Chevrolat		Afrotropical	BMNH, USNM
			4, 6, 88, 94	Trigonotarsus Guerin-Meneville		Australasian	ANIC
			3, 7, 11, 89	Trochorhopalus Kirsch		Afrotropical	USNM
		Litosomina	3, 6, 64		Eugnoristus Schoenherr	Afrotropical	BMNH
			1, 82	Sitophilus Schoenherr		Cosmopolitan	USNM
			1, 90		Tryphetus Faust	Oriental	USNM
		Diocalandrina	1, 7, 60	Diocalandra Faust		Oriental	USNM
			7, 68	Myocalandra Faust		Oriental	USNM
	Dryophthorini		7, 62	Dryophthorus Germar		Circumtropical	USNM
			1, 11, 86	Stenommatus Wollaston		New World	USNM
	Stromboscerini		61	Dryophthoroides Roelofs		Oriental	[12]
			1, 7, 70	Nephius (=Anius) Pascoe		Oriental	BMNH
			91	Xerodermus Lacordaire		Oriental	[11,12]

Figure 56. Cactophagus validus mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) detail of hypopharynx, mala, and maxillary palp, dorsal view; (d) detail of mala and maxillary palp, ventral view; and (e) labio-maxillary complex, ventral view.

Figure 57. Cosmopolites sordidus mouthparts: (a), epipharynx; (b) clypeus and labrum; (c) detail of mala and maxillary palp, dorsal view; (d) detail of mala and maxillary palp, ventral view; (e) detail of mala and maxillary palp, opposite side, ventral view; (f) labio-maxillary complex, ventral view; and (g) mandible and detail of cusps.

Figure 58. Cyrtotrachelus thompsoni mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) detail of hypopharynx, mala, and maxillary palp, dorsal view; (d) antenna, anterior view; (e) antenna, oblique lateral view; (f) detail of mala, ventral view; (g) labio-maxillary complex, ventral view; and (h) mandible.

Figure 59. Diathetes morio mouthparts: (a) epipharynx; (b) clypeus (incomplete) and labrum; (c) detail of hypopharynx, mala, and maxillary palp, dorsal view; (d) mandible; and (e) labio-maxillary complex, ventral view.

Figure 60. Diocalandra frumenti mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) detail of hypopharynx, mala, and maxillary palp, dorsal view; (d) mandible; and (e) labio-maxillary complex, ventral view.

Figure 61. Reproduction of Gardner’s ([12], p. 260) Plate V: “Larvae of Curculionidae. Figure 58. Himatinum lalli, ventral mouthparts. Figures 59 and 60. Phloeophagosoma aesculi. 59. Epipharynx. 60. Ventral mouthparts. Figures 61 and 62. Macrorhyncholus ventilaginis. 61. Mandible. 62. Spiracle. Figures 63 and 64. Trochorrhopalus [sic] balwanti. 63. Larva. 64. Caudal extremity, dorsal view. Figures 65–71. Anius [Nephius] pauperatus. 65. Maxillary mala and palp. 66. Caudal extremity, dorsal view. 67. Caudal extremity, ventral view. 68. Labium. 69. Larva. 70. Epipharynx. 71. Spiracle. Figures 72 and 73. Dryophthoroides parvungulis. 72. Epipharynx. 73. Maxillary mala and palp.”

Figure 62. Dryophthorus americanus mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) detail of hypopharynx, mala, and maxillary palp, dorsal view; and (d) labio-maxillary complex, ventral view.

Figure 63. Eucalandra setulosa mouthparts: (a) epipharynx; (b) mala and hypopharynx, dorsal view; (c) antenna, lateral view; (d) detail of mala and maxillary palp, ventral view; (e) mandible; and (f) labio-maxillary complex, ventral view.

Figure 64. Eugnoristus braueri mouthparts: (a) epipharynx; (b) clypeus (incomplete) and labrum; (c) hypopharynx, mala, and maxillary palp, dorsal view; (d) antenna, oblique-lateral view; (e) antenna, antero-lateral view; and (f) labio-maxillary complex, ventral view.

Figure 65. Foveolus c.f. maculatus mouthparts: (a) epipharynx; (b) clypeus (incomplete) labrum; (c) hypopharynx, mala, and maxillary palp, dorsal view; (d detail of mala and dorsal malar setae; (e) detail of mala and ventral malar setae; and (f) labio-maxillary complex, ventral view.

Figure 66. Probably Mesocordylus sp. mouthparts: (a) epipharynx; (b) clypeus (incomplete) and labrum; (c) detail of hypopharynx, mala and maxillary palp, dorsal view; (d) mandible; (e) detail of mala and ventral malar setae; and (f) labio-maxillary complex, ventral view.

Figure 67. Metamasius ritchiei mouthparts: (a) epipharynx; (b) clypeus (incomplete) and labrum; (c) maxillae and hypopharynx, dorsal view; (d) Metamasius hemipterus clypeus (incomplete) and labrum; (e) labio-maxillary complex, ventral view; and (f) thoracic spiracle.

Figure 68. Myocalandra sp. Mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) maxillae and hypopharynx, dorsal view; (d) spiracles; (e) mandibles; and (f) labio-maxillary complex, ventral view.

Figure 69. Nassophasis sp. Mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) maxillae and hypopharynx, dorsal view; (d) spiracles; (e) mandibles; and (f) labio-maxillary complex, ventral view.

Figure 70. Nephius (=Anius) pauperatus mouthparts: (a) epipharynx; (b) antenna, lateral view; (c) maxillae and hypopharynx, dorsal view; (d) mandible; (e) spiracles; and (f) labio-maxillary complex, ventral view. Th (L): thorax, left side; Th (R): thorax, right side; VII: 7th abdominal segment; VIII: 8th abdominal segment.

Figure 71. Odoiporus longicollis mouthparts: (a) epipharynx; (b) clypeus (incomplete) and labrum; (c) detail of hypopharynx, mala, and maxillary palp, dorsal view; (d) detail of mala and dorsal malar setae; (e) mandible; (f) detail of mala and ventral malar setae; and (g) labio-maxillary complex, ventral view.

Figure 72. Paramasius cristulatus mouthparts: (a) epipharynx; (b) labrum; (c) maxillae and hypopharynx, dorsal view; (d) mala, ventral view; (e) mandible, internally with scerotized process; and (f) labio-maxillary complex, ventral view.

Figure 73. Phacecorynes zamiae mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) maxillae and hypopharynx, dorsal view; (d) mandible; and (e) labio-maxillary complex, ventral view.

Figure 74. Polytus mellerborgii mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) maxillae and hypopharynx, dorsal view; (d) mandibles; and (e) labio-maxillary complex, ventral view.

Figure 75. Poteriophorus uhlemanni mouthparts: (a) epipharynx; (b) labium; (c) detail of maxilla and hypopharynx, dorsal view; and (d) labrum. Als: anterolateral setael; ams: anteromedian setae; dms: dorsal malar setae; lgs: ligular setae; lms: labral setae; mes: median epipharyngeal setae; pasps: posterior accessory sensory pores; pms: postmental setae; prms: premental setae; snp: sensory pores of epipharynx.

Figure 76. Rhabdoscelus prob. obscurus mouthparts: (a) epipharynx; (b) clypeus (incomplete) and labrum; (c) maxillae and hypopharynx, dorsal view; (d) detail of mala and dorsal malar setae; (e) detail of mala and ventral malar setae; and (f) labio-maxillary complex, ventral view.

Figure 77. Rhinostomus barbirostris mouthparts: (a) clypeus (without setae) and labrum; and (b) epipharynx.

Figure 78. Rhodobaenus tredecempunctatus mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) mala, maxillary palp, and hypopharynx, ventral view; (d) mandible; (e) detail, mala, ventral view; (f) detail, mala, dorsal view; and (g) labio-maxillary complex, ventral view.

Figure 79. Rhynchophorus palmarum mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) mala and maxillary palp, dorsal view; (d) detail, mala and hypopharynx, ventral view; (e) maxillae, hypopharynx, labium, dorsal view; and (f) labio-maxillary complex, ventral view.

Figure 80. Scyphophorus acupunctatus mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) mala, maxillary palp, and hypopharynx, dorsal view; (d) detail of mala and ventral malar setae; and (e) labio-maxillary complex, ventral view.

Figure 81. Sipalinus gigas mouthparts: (a) epipharynx; (b) clypeus (incomplete) and labrum; (c) detail, mala and maxillary palp, dorsal view; (d) mala and maxillary palp, ventral view; (e) labio-maxillary complex, dorsal view; and (g) labio-maxillary complex, ventral view (lms2: labial setae 2 broken).

Figure 82. Sitophilus spp. mouthparts: (a) Sitophilus granarius epipharynx; (b) Sitophilus linearis, labrum, clypeus, mandible, antenna and anterior margin of frons; (c) Sitophilus linearis, epipharynx; (d) Sitophilus oryzae, epipharynx; (e) Sitophilus oryzae, labrum, clypeus, and anterior margin of frons; (f) Sitophilus linearis, labio-maxillary complex, ventral view; and (g) Sitophilus granarius detail, mala and labium, ventral view.

Figure 83. Sparganobasis subcruciata mouthparts: (a) epipharynx, setae broken/weathered; (b) clypeus and labrum, setae broken/weathered; (c) mala and hypopharynx, dorsal view; (d) mandible; (e) detail, mala and dorsal malar setae, some setae broken/weathered; and (f) labio-maxillary complex, ventral view, some setae broken/weathered.

Figure 84. Sphenophorus spp. mouthparts: (a) Sphenophorus discolor, epipharynx; (b) Sphenophorus discolor; clypeus and labrum; (c) Sphenophorus aequalis, epipharynx; (d) Sphenophorus aequalis, clypeus and labrum; (e) Sphenophorus maidis, epipharynx; and (f) Sphenophorus maidis, clypeus (incomplete) and labrum.

Figure 85. Sphenophorus spp. mouthparts and spiracles: (a) Sphenophorus pontederiae, epipharynx; (b) Sphenophorus pontederiae, spiracles; (c) Sphenophorus maidis spiracles; (d) Sphenophorus maidis, maxillae and hypopharynx, dorsal view; (e) Sphenophorus maidis, maxillae and hypopharynx, dorsal view; (f) Sphenophorus maidis, detail, mala and labium, ventral view; (g) Sphenophorus maidis, antenna; (h) Sphenophorus maidis, mandible; and (i) Sphenophorus maidis, labio-maxillary complex, ventral view.

Figure 86. Stenommatus musae mouthparts: (a) epipharynx; (b) epipharynx, variation; (c) clypeus and labrum; (d) antennae; (e) mala, hypopharynx, maxillary palp, dorsal view; (f) mandible; (g) mandible; and (h) labio-maxillary complex, ventral view.

Figure 87. Temnoschoita sp. Mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) detail of hypopharynx and maxillae, dorsal view; (d) mandible; and (e) labio-maxillary complex, ventral view.

Figure 88. Trigonotarsus calandroides mouthparts: (a) epipharynx; (b) clypeus (incomplete) and labrum; (c) hypopharynx, and maxillary palp, dorsal view; (d) detail of mala and ventral malar setae; and (e) labio-maxillary complex, ventral view.

Figure 89. Trochorhopalus strangulatus mouthparts: (a) epipharynx; (b) clypeus and labrum; (c) detail of hypopharynx, mala, and maxillary palp, dorsal view; (d) mandible; and (e) labio-maxillary complex, ventral view.

Figure 90. Tryphetus incarnatus mouthparts: (a) epipharynx; (b) labrum and clypeus; (c) detail of hypopharynx, mala, and maxillary palp, dorsal view; (d) mandible; (e) spiracles; (f) detail, mala, hypopharynx, maxillary palp, dorsal view; and (g) labio-maxillary complex, ventral view. Th: thorax; III: 3rd abdominal segment; VIII: 8th abdominal segment.

Figure 91. Reproduction of Gardner ([11], 48) Plate VI: “Larvae of Curculionidae. Figures 93–96. Sipalus [Sipalinus] hypocrita Boh. 93. Maxillary mala, dorsal view. 94. Epipharynx. 95. Abdominal spricale. 96. Posterior extremity, dorsal view. Figures 97 and 98. Cyrtotrachelus longipes F. 97. Lateral view. ¹ (¹ In Figure 97 the numerals IX and X should have been interchanged). 98. Mandible. Figure 99. Calandra [Sitophilus] rugicollis Casey. Figure 100. Rhynchophorus ferrugienus Ol., posterior extremity in dorsal view. Figures 101 and 102. Odoiporus longicollis Ol. 101. Posterior extremity in dorsal view. 102. Mandible. Figures 103–105. Xerodermus himalayanus Mshl. 103. Labium. 104. Posterior extremity in dorsal view. 105. Spiracle. Figures 106–110. Cossonus binodosus Mshl. 106. Ventral mouthparts. 107. Abdominal spiracle. 108. Lateral view. 109. Epipharynx. 110. Mandible. Figure 111. Brachydemnus himalayensis Stebb., an abdominal spiracle.”

Figure 92. Yuccaborus lentiginosus mouthparts: (a) epipharynx; (b) clypeus (incomplete) and labrum; (c) detail of hypopharynx and maxillae, dorsal view; (d) mandible and antenna; and (e) labium, ventral view.

2. Materials and Methods

2.1. Specimens

Specimens included in this study are deposited in the following institutions, as indicated in Table 1 and Table 2:

Table 2. Material examined including locality data and depository.

Figure	USNMENT Code	Species	Determiner	Host	Location	Depository
56	USNMENT01448507	Cactophagus validus (LeConte)	R.T. Cotton		Leng 335	USNM
56	USNMENT01119907	Cactophagus validus (LeConte)	D.M.Anderson		California, Garden Grove, A.C. Davis	USNM
56	USNMENT01119908	Cactophagus validus (LeConte)	R.T. Cotton		Leng 335	USNM
57	USNMENT01448170	Cosmopolites sordidus (Germar)	D.M.Anderson	in banana stalk	Puerto Rico, Bayamon, 11.vi.1943, San Juan #8597, 43 9200	USNM
57	USNMENT01119912	Cosmopolites sordidus (Germar)	D.M.Anderson	in trunks-banana	Florida, Forth Myers, 15.ii.’44, 44 2934	USNM
58	USNMENT01119896	Cyrtotrachelus thompsoni Alonso-Zarazaga & Lyal	Mr. Lee	Bamboo	Taiwan: E120.63108, N23.84535, 26.viii.2015	USNM
59	USNMENT01160268	Diathetes morio Pascoe	R. Oberprieler	Pandanus	Australia: 16°04′07″S, 145°27′49″E, QLD, Daintree NP, Pilgrim Sands, 19.Feb. 1998, R. Oberprieler, RO507	ANIC
60	USNMENT01448168	Diocalandra taitensis (Guerin-Meneville)	DMAnderson	petiole of coconut	USA: HI, Honolulu, 2-20-29, O.H.S.	USNM
62	USNMENT01448160	Dryophthorus americanus Bedel	DMAnderson	in rotting pine	USA: MD, near Plummers Island, 25.vii.1913, Schwarz & Barber	USNM
62	USNMENT01448161	Dryophthorus americanus Bedel	DMAnderson	Old, rotten chestnut	USA: VA, Vienna, 19.iii.1942, J.C. Bridwell	USNM
63	USNMENT01448167	Eucalandra setulosa (Gyllenhal)	D.M.Anderson	in stem, solid bamboo	Venezuela, Yaracuy, 23.x.’43, McClure, #24	USNM
64	USNMENT01070971	Eugnoristus braueri Kolbe	N/A	attacking coconut	Seychelles, 19	BMNH
65	USNMENT01160269	Foveolus c.f. maculatus O’Brien	de Madeiros	Euterpe oleracea	Brazil:1-1.497, -48.461, CU069 Pará, Belem, Ilha do Combu, 29.v.2012, B. de Madeiros	MZSP
66	USNMENT01448502	Mesocordylus (Prob.) sp. (larva & pupa)	Chamorro	Ex: Papyrus	Costa Rica: Port intercepted, 25.ii.2017	USNM
67	USNMENT01448165	Metamasius (ritchiei Marshall?)	R.T. Cotton	from pineapple plants	Panama, Canal Zone, Summit	USNM
67	USNMENT01448166	Metamasius hemipterus (Linnaeus)	R.T. Cotton		Leng 335	USNM
67	USNMENT01448164	Metamasius ritchiei Marshall	R.T. Cotton		Jamaica	USNM
67	USNMENT01448162	Metamasius ritchiei Marshall	D.M.Anderson	Pineapple	Jamaica, nr. Kingston, Sept. 16, 1917, A.H. Ritchie colr., A-500	USNM
67	USNMENT01119914	Metamasius ritchiei Marshall	D.M.Anderson	Pineapple	Jamaica, nr. Kingston, Sept. 16, 1917, A.H. Ritchie colr., A-500	USNM
67	USNMENT01119913	Metamasius ritchiei Marshall	R.T. Cotton	in pineapple	Leng 335, Jamaica, W.I.	USNM
67	USNMENT01448163	Metamasius ritchiei Marshall	R.T. Cotton	in pineapple	Leng 335, Jamaica, W.I.	USNM
68	USNMENT01448173	Myocalandra sp.	W.H. Anderson	dried bamboo sticks	Japan, 28.i.1941, 41 1683	USNM
68	USNMENT01448172	Myocalandra sp.	W.H. Anderson	dried bamboo sticks	Japan, 28.i.1941, 41 1683	USNM
69	USNMENT01070977	Nassophasis sp.	N/A	Calanthe cardioglossa	Vietnam: intercepted Miami CBP; 6/16/2003, #246766	USNM
70	USNMENT01070967	Nephius (=Anius) pauperatus (Pascoe)	N/A	Bark Alaeocarpus	INDIA: Samsing, Kalimpong Bengels, N.G. Chatterjee +Mite, x.1933; BMNH 1949-505, T.2194J.77(S.E. 1631)	BMNH
71	USNMENT01160265	Odoiporus longicollis (Linnaeus)	M.L. Chamorro	In Musa	Taiwan, Sun Moon Lake, 23.vii.2015	USNM
72	USNMENT01160257	Paramasius cristulatus Vannin	B. de Madeiros	Clusia c.f. nemorosa fruit	Brazil: Amazonas, Manaus, Reserva Duche, -2.93024, -59.97397, 20.v.2012, F. Cabral	INPA
73	USNMENT01448191	Phacecorynes zamiae (Gyllenhal)	D.M.Anderson	Encephalartos caffra	Africa, Port Elizabeth, 21.v.36, EQA 36291	USNM
74	USNMENT01448169	Polytus mellerborgii (Boheman)	DMAnderson	banana corm	USA: HI, Honolulu, 3-27-35, O.H.Swezey	USNM
75	USNMENT01119878	Poteriophorus uhlemanni (Schultze)	Chamorro		Taiwan, Lanyu	USNM
75	USNMENT01070986	Poteriophorus uhlemanni (Schultze)	Chamorro		Taiwan, Lanyu	USNM
75	USNMENT01070985	Poteriophorus uhlemanni (Schultze)	Chamorro		Taiwan, Lanyu	USNM
76	USNMENT01448505	Rhabdoscelus obscurus (Boisduval)?	R.T. Cotton		Tahiti	USNM
77	USNMENT01448185	Rhinostomus barbirostris (Fabricius)	W.H. Anderson		Brazil, sent by G. Bondar, rec’d 16.x.1942	USNM
78	USNMENT01448193	Rhodobaenus tredecimpunctatus (Illiger)	D.M. Anderson	Stems of Eupatotium	Aug. 5, 1917. Hopk. U.S. Forest insect colln.	USNM
78	USNMENT01448194	Rhodobaenus tredecimpunctatus (Illiger)	D.M. Anderson	Stems of Eupatotium	Aug. 5, 1917. Hopk. U.S. Forest insect colln.	USNM
78	USNMENT01448184	Rhynchophorus cruentatus (Fab.)	R.T. Cotton		Leng 335	USNM
79	USNMENT01448183	Rhynchophorus palmarum (L.) (Prob.)	W.H. Anderson	in pineapple fruit	Mexico, Loma Bonita, Oaxaca 17.vi.’47, El Paso #49108, 47 8789	USNM
80	USNMENT01075012	Scyphophorus acupunctatus Gyllenhal			Mex: Magdalena, Sonora	USNM
80	USNMENT01075013	Scyphophorus acupunctatus Gyllenhal	R.T. Cotton		Arizona Leng 335	USNM
80	USNMENT01075007	Scyphophorus acupunctatus Gyllenhal	M.L. Chamorro		Arizona, Fort Grant, Hobbard #869	USNM
80	USNMENT01075013	Scyphophorus acupunctatus Gyllenhal	R.T. Cotton		Arizona Leng 335	USNM
80	USNMENT01119877	Scyphophorus yuccae Horn	R.T. Cotton		Arizona Leng 335	USNM
80	USNMENT01448506	Scyphophorus yuccae Horn	D.M. Anderson		California, Arrowhead, Apr. ’93, U.S.D.A. No. 4083	USNM
81	USNMENT01070976	Sipalinus gigas (Fabricius)	D.M. Anderson	“Acrylic sheets”	Japan:intercepted 04/23/75, USDA 75-7265, New York, NY CBP	USNM
82	USNMENT01160334	Sitophilus granarius (Linnaeus)	D.M. Anderson	Valonea nuts	Greece, 23.vi.1937, NY 72028	USNM
82	USNMENT01160255	Sitophilus linearis (Herbst)	D.M. Anderson	Tamarind bean pods	Trinidad, 22.iii.1942, 42 3894	USNM
82	USNMENT01448500	Sitophilus oryzae (Linnaeus)	D.M. Anderson	In Chestnut	Italy?, 31.i.1944, 44 2571	USNM
83	USNMENT01160266	Sparganobasis subcruciata Marshall	R. Oberprieler	Oil palm plantation	Papua New Guinea, 8°51′14S, 147°41′43E,28.IX.2010, C.F. DEWHURST	ANIC
84, 85	USNMENT01119910	Sphenophorus [Calendra] sp.		In Tule, in roots	Louisiana, Morse, 23.viii.1943, Spec. Surv. #1581, 43 13469	USNM
84, 85	USNMENT01448181	Sphenophorus aequalis Gyllenhal	R.T. Cotton		Leng 336, Texas, R.T. Cotton	USNM
84, 85	USNMENT01119911	Sphenophorus cariosa (Olivier)	D.M. Anderson	Cyperus exaltatus	Texas, Pierce, Dec. 3, 1907, J.D. Mitchell	USNM
84, 85	USNMENT01448182	Sphenophorus discolor (Mannerheim)	R.T. Cotton		Leng 336, R.T. Cotton	USNM
84, 85	USNMENT01448179	Sphenophorus maidis Chittenden	D.M. Anderson		USA. South Carolina., Lee Co., Meredith, O.L. Cartwright, 1928	USNM
84, 85	USNMENT01119906	Sphenophorus maidis Chittenden	D.M. Anderson	in corn	USA., South Carolina, U.S.D.A. 2809, Box 13/13	USNM
84, 85	USNMENT01448180	Sphenophorus pertinax (Olivier)	R.T. Cotton		Leng 336, R.T. Cotton	USNM
84, 85	USNMENT01448177	Sphenophorus pontederiae Chittenden	D.M. Anderson	in rootstocks Pontederia cordata	Massachusetts, Stoughton, aug. 1924, D.H. Blake collr.	USNM
84, 85	USNMENT01119909	Sphenophorus pontederiae Chittenden	D.M. Anderson	in rootstocks Pontederia cordata	Massachusetts, Stoughton, aug. 1924, D.H. Blake collr.	USNM
84, 85	USNMENT01448178	Sphenophorus pontederiae Chittenden	R.T. Cotton		Leng 336	USNM
86	USNMENT01448176	Stenommatus musae Marshall	Anderson/Swezey	ex. Banana corm	USA, Honolulu, 27.iii.1935, O.H. Swezey	USNM
86	USNMENT01448175	Stenommatus musae Marshall	Anderson/Swezey	ex. Banana corm	USA, Honolulu, 27.iii.1935, O.H. Swezey	USNM
86	USNMENT01448174	Stenommatus musae Marshall	Anderson/Swezey	ex. Banana corm	USA, Honolulu, 27.iii.1935, O.H. Swezey	USNM
87	USNMENT00677022	Temnoschoita sp.	D.M. Anderson	Coconut palm stems	Togo, intercepted New York, NY CBP, 05/21/80 #013366	USNM
88	USNMENT01160267	Trigonotarsus calandroides Guérin-Méneville	R. Oberprieler	Xanthorrhoea stump	Australia: ACT, Uriarra Rd. 7.vii.1976, D.P. Crane	ANIC
89	USNMENT01448190	Trochorhopalus strangulatus Gyllenhal	D.M. Anderson	in sugar cane	Victorias, Occ. Negras, Nov. 10, 1929, Pierce coll., # CC.80	USNM
89	USNMENT01448120	Trochorhopalus strangulatus Gyllenhal	D.M. Anderson	in sugar cane	Victorias, Occ. Negras, Nov. 10, 1929, Pierce coll., # CC.80	USNM
89	USNMENT01448192	Trochorhopalus strangulatus Gyllenhal	D.M. Anderson	in sugar cane	Victorias, Occ. Negras, Nov. 10, 1929, Pierce coll., # CC.80	USNM
90	USNMENT01119895	Tryphetus incarnatus Gyllenhal	M.L. Chamorro	Fabaceae seed	Thailand, intercepted in Los Angeles CBP, 3.xi.2015	USNM
92	USNMENT01448501	Yuccaborus lentiginosus Casey	D.M. Anderson		USA, Texas, Yucca Ridge, 10 mi N.E. Brownsvile, 4.vi.1904, H.S. Barber	USNM

Australian National Insect Collection, ANIC;

British Museum of Natural History, BMNH;

Instituto Nacional de Pesquisas de Amazonias, INPA;

Museu Zoologico de São Paulo, MZSP;

National Taiwan Normal University, Taipei, NTNU; and

United States National Museum, USNM.

2.2. Slides/Associations

Associations and identifications were made by competent authorities (listed in Table 2 of the material examined) based on larva-pupa-adult associations, collected from known host plant, and/or through rearing (Figure 93 and Figure 94). Therefore, ambiguity or uncertainty are indicated with a pound symbol (#) next to the taxon name or remains uncategorized and is listed at the bottom of the character (couplet). Taxon names with an asterisk (*) indicate polymorphism. When multiple species of a genus were available for study, these were examined and in the case of Sitophilus and Sphenophorus, also illustrated and coded. The identity of Mesocordylus is based on identification of the pupa and therefore it is considered tentative in this study. However, the larva is identified as belonging in the subtribe Orthognathina. Paramasius is here included as a separate genus from Metamasius; however, this was done in an attempt to uncover potential characters that may confirm synonymy or possibly resurrection from Metamasius.

Figure 93. Phacecorynes variegatus: (a) adult; (b) variable form, adult; (c) larva, lateral view; (d) larva, lateral view partially concealled; (e) pupa, ventral view; Phacecorynes sommeri: (f) adult; (g) larva, lateral view; and (h) pupa, lateral view. Photographs courtesy of Rolf Oberprieler.

Figure 94. Sipalinus gigas.: (a) adult; (b) external damage; (c) larva, caudal view; (d) larva, lateral view; Trigonotarsus calandroides (e) adult, lateral view;: (f) larva, lateral view; (g) larva undergoing peristaltic behavior, lateral view; and (h) pupa, ventral view. Photographs courtesy of Rolf Oberprieler.

All of Cotton’s and Anderson’s slides housed at the USNM were examined. In the interest of time, not all were given a unique identifier or included in Table 2. Incomplete taxa for which specimens were not available for examination are Dynamis, Dryophthoroides, Rhinostomus, and Xerodermus. Their inclusion in the key largely reflects literature sources and and therefore were not included in all couplets. Prodioctes is not included and information on the larva of this taxon remains elusive. The only specimen available for study of Rhinostomus was of a prepared slide containing only the labrum/epipharynx; consequently the head, remained of the mouthparts, thorax, and abdomen were not examined. Finally, variation across instars or populations was not significantly studied.

2.3. Slide Preparation

Slide preparation of the mouthparts follows Chamorro et al. [14] with the additional step of clearing the mouthparts with 10% KOH prior to placing them on the mounting medium (PVA #6371A, Bioquip Products). The reader should consult May [10,15] for a detailed description of slide preparation procedures. Her work is a fundamental resource for the study of the immature stages of weevils.

2.4. Drawings and Imaging

Pencil drawings were rendered by the author with the aid of a drawing tube mounted on a Zeiss Axiophot compound microscope, for the mouthparts, and a Zeiss Discovery v8 stereomicroscope for the head, thorax, and abdomen of large specimens. The pencil drawings were scanned and imported as templates into Adobe Illustrator (Adobe Systems) to render digital vector graphics. Plates were arranged and labeled with Adobe Illustrator and Adobe InDesign (for color photographs).

Images were taken with an Olympus PEN5 camera mounted on a Zeiss Discovery v8 stereomicroscope. Individual images were taken at different focal planes and combined to create a single image with Zerene Stacker (Zerene Systems, LLC, Richland, WA, USA).

2.5. Terminology

Terminology follows Oberprieler et al. [16] and Chamorro et al. [17] (Figure 74). Initially, character and character state management and coding were facilitated with the use of the program vSysLab: a virtual Systematics Laboratory [18] and LUCID (lucidcentral.org).

2.6. Key: Structure and User Instructions

The synoptic key follows Holloway [19] and this publication should be consulted for relevant references and for a detailed description and example on how to use a synoptic key. Briefly, a synoptic key can best be described as a static (paper) LUCID key, which allows the user to identify a specimen using any combination of characters (couplets). A synoptic key is multi-entry, in contrast to a traditional, single entry dichotomous key. A LUCID key will be generated as a follow-up to this study.

This study focuses largely on the mouthparts, however some characters of the head, chaetotaxy, and overall body characters, such as thoracic and abdominal spiracles and shape of posterior segments (VIII and IX), are also included. The user is encouraged to first eliminate taxa by referencing the included characters of the head, general body form, spiracles, caudal processes, and, following dissection of the mouthparts, the chaetotaxy of the labrum such as als and ams of the epipharynx (indicated in grey). The key is arranged into the following nine categories, each containing a variable number of couplets (characters): habitus (3 couplets), head (3), thorax (1), abdomen (4), labrum/epipharynx (20), mandibles (4), hypopharynx (2), maxillae (10), and labium (5). The taxon chosen to illustrate a given character is underlined for each couplet. The taxon or taxa chosen to illustrate a given character state (lead) is underlined. Taxa not included in a given couplet are listed at the end of each couplet. Information on possible host commodity/host plant is included in Table 2 for most specimens as part of the material examined and this information, as well as generalized distribution data included in Table 2, may prove helpful in the identification process. Finally, as suggested by Marshall [20] (p. 395): “If the key below is used to identify specimens involved in published research (print or online), please cite this work and include the full citation in the list of references.”

To begin, select any character (couplet) (but preferably ones indicated in grey, which tend to be diagnostic at higher levels or do not require dissections of the mouthparts) and identify the character state (lead) that best describes the feature observed on the specimen. Each state is illustrated to avoid uncertainty. List the taxa under the selected character state (lead). To narrow down the list, choose a subsequent character (couplet), determine which state (lead) best describes your specimen and delete the name(s) that do not appear on the list under that state (lead). Continue this elimination process until a single taxon name remains.

3. Results

The following diagnostic characters were listed by May [15] (p. 663) to distinguish Dryophthorinae larvae. Characters 1, 2, 11, and 12 are among the most salient features.

“Larva, 1. Body shape typically expanded between Abd IV and Abd V, narrowing abruptly (seed inhabiting forms such as Sitophilus Schoenherr are subspherical). 2. Abd VIII/IX together forming a depressed dorsal disk. 3. Dorso- and ventropleural abdominal areas subdivided into 2, 3, or 4 superimposed lobes. 4. Anus subterminal or ventral. 5. Head usually free, longer than wide, entire behind; postoccipital condyles obsolete. 6. Labrum rounded, rarely distinctly trilobate. 7. Tormae well developed, subparallel, or convergent, often joined by a basal bridge. 8. Maxilla with dorsal malal setae usually branched; some setae of other mouthparts may also be branched. 9. Hypopharynx often densely pubescent. 10. Hyphopharyngeal bracon clear (Sitophilus granarius and S. zeamais are exceptions). 11. Spiracles ovate-fringed with an outer skin fold narrowly pigmented, or subtriangular with unpigmented skin fold; aligned vertically with airtubes dorsal. 12. Spiracles of Abd VIII positioned on dorsal disk, caudad.”

Known larvae of some Molytinae (Anderson’s [9] Cholini and most Hylobiini) resemble dryophhtorine larvae in that they possess almost identical abdominal spiracles [9]. Anderson [9] stressed the importance of the orientation of abdominal spiracles on segment VIII as the key feature distinguishing dryophthorines from these groups. In Dryophthorinae, the spiracular airtubes of segment VIII are directed caudad and not dorsad. The larvae of at least three molytine genera, Sternechus Schoenherr, Anchonus Schoenherr, and Heilipus Germar, possess abdominal spiracles with airtubes directed nearly posterad [9].

The following key presents illustrated characters (Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, Figure 8, Figure 9, Figure 10, Figure 11, Figure 12, Figure 13, Figure 14, Figure 15, Figure 16, Figure 17, Figure 18, Figure 19, Figure 20, Figure 21, Figure 22, Figure 23, Figure 24, Figure 25, Figure 26, Figure 27, Figure 28, Figure 29, Figure 30, Figure 31, Figure 32, Figure 33, Figure 34, Figure 35, Figure 36, Figure 37, Figure 38, Figure 39, Figure 40, Figure 41, Figure 42, Figure 43, Figure 44, Figure 45, Figure 46, Figure 47, Figure 48, Figure 49, Figure 50, Figure 51, Figure 52, Figure 53, Figure 54 and Figure 55) useful to distinguish known dryophthorine larvae. In addition, detailed illustrations of the mouthparts of the following 36 genera are provided at the end of the key (Figure 56, Figure 57, Figure 58, Figure 59, Figure 60, Figure 61, Figure 62, Figure 63, Figure 64, Figure 65, Figure 66, Figure 67, Figure 68, Figure 69, Figure 70, Figure 71, Figure 72, Figure 73, Figure 74, Figure 75, Figure 76, Figure 77, Figure 78, Figure 79, Figure 80, Figure 81, Figure 82, Figure 83, Figure 84, Figure 85, Figure 86, Figure 87, Figure 88, Figure 89, Figure 90, Figure 91 and Figure 92): Cactophagus LeConte (Figure 56), Cosmopolites Chevrolat (Figure 57), Cyrtotrachelus Schoenherr (Figure 58), Diathetes Pascoe (Figure 59), Diocalandra Faust (Figure 60), Dryophthoroides Roelofs (Figure 61), Dryophthorus Germar (Figure 62), Eucalandra Faust (Figure 63), Eugnoristus Schoenherr (Figure 64), Foveolus Vaurie (Figure 65), Mesocordylus Lacordaire (Figure 66), Metamasius Horn (Figure 67), Myocalandra Faust (Figure 68), Nassophasis Waterhouse (Figure 69), Nephius Pascoe (Figure 70), Odoiporus Chevrolat (Figure 71), Paramasius Kuschel (currently a junio synonym of Metamasius) (Figure 72), Phacecorynes Schoenherr (Figure 73), Polytus Faust (Figure 74), Poteriophorus Schoenherr (Figure 75), Rhabdoscelus Marshall (Figure 76), Rhinostomus Rafinesque (Figure 77, only labrum/epipharynx), Rhodobaenus LeConte (Figure 78), Rhynchophorus Herbst (Figure 79), Scyphophorus Schoenherr (Figure 80), Sipalinus Marshall (Figure 81), Sitophilus Schoenherr (Figure 82), Sparganobasis Marshall (Figure 83), Sphenophorus Schoenherr (Figure 84 and Figure 85), Stenommatus Wollaston (Figure 86), Temnoschoita Chevrolat (Figure 87), Trigonotarsus Guerin-Meneville (Figure 88), Trochorhopalus Kirsch (Figure 89), Tryphetus Faust (Figure 90), Xerodermus Lacordaire (Figure 91), and Yuccaborus LeConte (Figure 92). Dynamis Chevrolat is not illustred. Among characters considered important to distinguish among the tribes and genera are: the number of frontal setae of the head, the shape of the thoracic and abdominal spiracles, the shape of abdominal segments VIII and IX, the chaetotaxy of the labrum and epipharynx, and the chaetotaxy and overall shape of the mala. Photographs of live adult, larva, and pupa in situ in their hosts are included for Phacecorynes, Sipalinus, and Trigonotarsus (Figure 93 and Figure 94).

Figure 1. Larva, lateral view: (a) Sitophilus; (b) Stenommatus; (c) Diocalandra; (d) Tryphetus; (e) Eucalandra; and (f) Nephius.

Figure 2. Larva, lateral view: (a) Phacecorynes; (b) Sphenophorus; (c) Scyphophorus; and (d) Temnoschoita.

Figure 3. Larva, lateral view: (a) Cosmopolites; (b) Mesocordylus (probably); (c) Eugnoristus; (d) Foveolus; (e) Metamasius; (f) Nassophasis; (g) Odoiporus; (h) Paramasius; and (i) Trochorhopalus.

Figure 4. Larvae, lateral view: (a) Cyrtotrachelus; (b) Diathetes; (c) Poteriophorus; (d) Sipalinus; (e) Sparganobasis; and (f) Trigonotarsus.

Figure 5. Thorax and abdomen, larva, lateral view: (a) Phacecorynes zamiae; and (b) Eugnoristus braueri.

Figure 6. Head, larva, dorsal view: (a) Mesocordylus; (b) Diathetes; (c) Eugnoristus; (d) Foveolus; (e) Odoiporus; (f) Paramasius; (g) Phacecorynes; (h) Sparganobasis; and (i) Trigonotarsus.

Figure 7. Head, larva, dorsal view: (a) Cyrtotrachelus; (b) Eucalandra; (c) Nephius (=Anius); (d) Cosmopolites; (e) Dryophthorus; (f) Diocalandra; (g) Myocalandra; (h) Nassophasis; (i) Polytus; (j) Rhodobaenus; (k) Rhynchophorus; (l) Poteriophorus; (m) Sphenophorus maidis; (n) Sphenophorus pontederiae; and (o) Trochorhophalus.

Figure 8. Head, larva, dorsal view: (a) Cyrtotrachelus; and (b) Diocalandra.

Figure 9. Head, dorsal view and detail of antenna: (a) Nephius (=Anius); and (b) Poteriophorus.

Figure 10. Thoracic spiracles, larva: (a) Cosmopolites sordidus; (b) Metamasius ritchie; (c) Phacecorynes zamiae; (d) Nephius (=Anius) pauperatus; (e) Trochorhopalus strangulatus; and (f) Rhynchophorus palmarum.

Figure 11. Thoracic and abdominal spiracles, larva: (a) Metamasius; (b) Phacecorynes; (c) Rhodobaenus; (d) Stenommatus; (e) Trochorhopalus; (f) Cosmopolites; and (g) Rhynchophorus.

Figure 12. Larvae, lateral view: (a) Nephius (=Anius); (b) Phacecorynes.

Figure 13. Larvae, lateral view: (a) Eugnoristus (abdomen only); (b) Phacecorynes; and (c) Nephius (=Anius).

Figure 14. Segments VIII and IX, larva, caudal view: (a) Cosmopolites; (b) Metamasius; (c) Myocalandra; (d) Nassophasis; (e) Phacecorynes; (f) Rhodobaenus; (g) Rhynchophorus; (h) Stenommatus; and (i) Trochorhopalus.

Figure 15. Labrum, larva: (a) Poteriophorus sp.; and (b) Metamasius hemipterus; lms1–3: labral seta.

Figure 16. Labrum, larva: (a) Cosmopolites; (b) Myocalandra; (c) Rhodobaenus; and (d) Sphenophorus maidis.

Figure 17. Epipharynx, larva: (a) Phacecorynes; (b) Rhodobaenus; and (c) Polytus.

Figure 18. Epipharynx, larva: (a) Myocalandra; and (b) Cyrtotrachelus.

Figure 19. Epipharynx, larva: (a) Diocalandra; (b) Metamasius; (c) Nephius (=Anius); (d) Trochorhopalus; (e) Eugnoristus; and (f) Phacecorynes.

Figure 20. Epipharynx, larva: (a) Diocalandra; (b) Eugnoristus; (c) Metamasius; (d) Trochorhopalus; and (e) Sipalinus.

Figure 21. Epipharynx, larva: (a) Diocalandra; (b) Metamasius; and (c) Phacecorynes.

Figure 22. Epipharynx, larva: (a) Sitophilus; (b) Eucalandra; and (c) Polytus.

Figure 23. Epipharynx, larva: (a) Tryphetus; (b) Sphenophorus; (c) Phacecorynes; and (d) Rhynchophorus.

Figure 24. Epipharynx, larva: (a) Eucalandra; (b) Metamasius; (c) Temnoschoita; (d) Stenommatus; and (e) Trochorhopalus.

Figure 25. Epipharynx, larva: (a) Tryphetus; (b) Poteriophorus; (c) Sipalinus; (d) Yuccaborus; (e) Rhynchophorus; and (f) Cyrtotrachelus. Als1–3: anterolateral setae of epipharynx.

Figure 26. Epipharynx, larva: (a) Cactophagus; (b) Eucalandra; and (c) Sipalnus.

Figure 27. Epipharynx, larva: (a) Phacecorynes; (b) Temnoschoita; (c) Poteriophorus; and (d) Rhinostomus. Mes3: median epipharyngeal setae; ams1, 2: anteromedian setae of epipharynx.

Figure 28. Epipharynx, larva: (a) Poteriophorus; (b) Metamasius; and (c) Yuccaborus. Mes3: median epipharyngeal setae; ams1, 2: anteromedian setae of epipharynx.

Figure 29. Epipharynx, larva: (a) Eucalandra; (b) Phacecorynes; and (c) Rhodobaenus.

Figure 30. Epipharynx, larva: (a) Foveolus; (b) Cosmopolites; and (c) Rhinostomus.

Figure 31. Epipharynx, larva: (a) Sphenophorus pontederiae; and (b) Nephius (=Anius).

Figure 32. Epipharynx, larva: (a) Sphenophorus maidis; and (b) Nassophasis.

Figure 33. Epipharynx, larva: (a) Nephius (=Anius); (b) Eugnoristus; (c) Sipalinus; and (d) Yuccaborus.

Figure 34. Epipharynx, larva: (a) Nassophasis; (b) Rhynchophorus palmarum; (c) Yuccaborus.

Figure 35. Mandible, larva: (a) Eucalandra; (b) Nassophasis; and (c) Polytus.

Figure 36. Mandible, larva: (a) Cyrtotrachelus; and (b) Polytus.

Figure 37. Mandible, larva: (a) Cyrtotrachelus; and (b) Polytus.

Figure 38. Head and mandibles, larva, anterior view: (a) Dryophthorus; and (b) Diocalandra.

Figure 39. Hypopharynx, mala, and maxillary palp, larva, dorsal view: (a) Myocalandra; and (b) Nassophasis.

Figure 40. Hypopharynx, mala, and maxillary palp, larva, dorsal view: (a) Diocalandra; (b) Polytus; (c) Temnoschoita; and (d) Sipalinus.

Figure 41. Mala and maxillary palp, larva, dorsal view: (a) Cactophagus; (b) Cosmopolites; and (c) Rhynchophorus.

Figure 42. Mala and maxillary palp, larva, dorsal view: (a) Dryophthorus; (b) Sipalinus; (c) Rhodobaenus; and (d) Trigonotarsus.

Figure 43. Hypopharynx, mala, and maxillary palp, larva, dorsal view: (a) Sipalinus; (b) Poteriophorus; (c) Nephius (=Anius); and (d) Cyrtotrachelus. Dms: dorsal malar setae.

Figure 44. Hypopharynx, mala, and maxillary palp, larva, dorsal view: (a) Stenommatus; and (b) Rhynchophorus.

Figure 45. Hypopharynx, mala and maxillary palp, larva, dorsal view: (a) Tryphetus; (b) Myocalandra; (c) Stenommatus (d) Eucalandra; (e) Odoiporus; (f) Rhynchophorus; (g) Sipalinus; and (h) Cyrtotrachelus.

Figure 46. Hypopharynx, mala and maxillary palp, larva, dorsal view: (a) Cactophagus; and (b) Cosmopolites.

Figure 47. Mala and maxillary palp (d only), larva, dorsal view: (a) Rhodobaenus; (b) Temnoschoita; (c) Myocalandra; and (d) Eucalandra.

Figure 48. Mala and maxillary palp, larva, dorsal view: (a) Rhodobaenus; (b) Diocalandra; (c) Eucalandra; (d) Poteriophorus; (e) Temnoschoita; and (f) Sipalinus.

Figure 49. Mala, larva, dorsal view: (a) Cosmopolites; (b) Polytus; (c) Sipalinus; and (d Nassophasis.

Figure 50. Mala, larva, ventral view: (a) Tryphetus; and (b) Cyrtotrachelus.

Figure 51. Labium, labio-maxillary complex: (a) Rhynchophorus; and (b) Sphenophorus.

Figure 52. Labium, larva: (a) Poteriophorus; (b) Eucalandra; and (c) Yuccaborus. Lgs1, 2: ligular setae.

Figure 53. Labium, larva: (a) Stenommatus; and (b) Polytus.

Figure 54. Labium, larva: (a) Dryophthorus; and (b) Cosmopolites.

Figure 55. Labium, larva: (a) Phacecorynes; (b) Sipalnus; (c) Cosmopolites; and (d) Nephius.

3.1. Synoptic Key to Larval Dryophthorinae

3.1.1. Habitus

1. Body length of mature larva

a. 

Small (~2–8 mm) (Figure 1)

Diocalandra*, Dryophthoroides, Dryophthorus, Eucalandra*, Myocalandra*, Nephius (=Anius), Polytus, Stenommatus, Tryphetus, Xerodermus

b. 

Medium (~8–16 mm) (Figure 2 and Figure 3)

Cactophagus, Cosmopolites, Diathetes*, Diocalandra*, Eucalandra*, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Myocalandra*, Nassophasis, Odoiporus, Paramasius, Phacecorynes, Poteriophorus*, Rhabdoscelus, Rhodobaenus, Scyphophorus, Sparganobasis*, Sphenophorus, Temnoschoita, Trochorhopalus

c. 

Large (~16–40 mm) (Figure 4)

Cyrtotrachelus, Diathetes*, Dynamis, Poteriophorus*, Rhinostomus, Rhynchophorus, Sipalinus, Sitophilus, Sparganobasis*, Trigonotarsus, Yuccaborus

2. Expansion of abdomen ventrolaterally from segments II, III, or IV to V or VI, abruptly narrowed posterad

a. 

Present

Cactophagus, Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Dynamis [13], Eucalandra, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sparganobasis, Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Xerodermus [11], Yuccaborus

b. 

Absent

Sitophilus, Tryphetus

3. Location of anus (=position of segment X) (Figure 5)

a. 

Ventral, subapical

Cactophagus, Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Dynamis [13], Eucalandra, Foveolus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhinostomus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sparganobasis, Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Xerodermus [11], Yuccaborus

b. 

Terminal

Eugnoristus, Sitophilus, Tryphetus

3.1.2. Head

1. Number of setae on frons (fs) (Figure 6 and Figure 7)

a. 

8 (4 pairs) (fs1 absent)

Cyrtotrachelus#

b. 

10 (5 pairs)

Cactophagus, Cosmopolites, Diathetes, Diocalandra (fs1 minute), Dynamis [13], Eucalandra, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhinostomus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sparganobasis, Sphenophorus, Sitophilus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus, Yuccaborus

c. 

12 (6 pairs)

Dryophthorus, Stenommatus

Not included: Dryophthoroides, Xerodermus

2. Minute, clumped asperites (leopard-like) surface (Figure 8)

a. 

Prominent laterally and medially

Cyrtotrachelus

b. 

Absent

Cactophagus, Cosmopolites, Diathetes, Diocalandra, Dryophthorus, Eucalandra, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sitophilus, Sparganobasis, Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus, Yuccaborus

Not included: Dryophthoroides, Xerodermus

3. Sensorium of antenna (Figure 9)

a. 

Apical, convex sensorium moderately sized in relation to cushion-like, basal segment

Cactophagus, Cosmopolites, Cyrtotrachelus, Diathetes, Dynamis [13], Eucalandra, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Nassophasis, Odoiporus, Paramasius, Phacecorynes, Polytus#*, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sparganobasis, Sphenophorus, Temnoschoita, Trigonotarsus, Trochorhopalus, Yuccaborus (seemingly 2 sensoria)

b. 

Conical, sensorium relatively enlarged

Diocalandra, Dryophthorus, Myocalandra#, Nephius (=Anius), Polytus#*, Sitophilus, Stenommatus, Xerodermus [11], Tryphetus

Not included: Dryophthoroides (but possibly b), Rhinostomus

3.1.3. Thorax

1. Relative length of orifice and airtube of thoracic spiracle (Figure 10)

a. 

Orifice 4 times longer than air tube

Cosmopolites, Temnoschoita, Yuccaborus#*

b. 

Orifice 3–4 times longer than air tube (elongate)

Cactophagus, Metamasius ritchei*, Odoiporus, Rhabdoscelus*, Sparganobasis, Sphenophorus*, Trigonotarsus

c. 

Orifice 2.5–2 times longer than air tube length

Diocalandra, Eugnoristus, Foveolus, Paramasius, Phacecorynes, Rhabdoscelus*, Sitophilus granarius*, Sphenophorus pontederiae, Tryphetus

d. 

Orifice as long as air tube

Diathetes, Nephius (=Anius), Nassophasis, Scyphophorus, Sitophilus granarius*, Sphenophorus maidis, Sphenophorus cariosus, Xerodermus [11]

e. 

Orifice shorter than length of air tube (less than 3/4 length)

Drophthorus, Metamasius ritchiei?* (USNMENT01448165), Mesocordylus#, Myocalandra, Polytus, Poteriophorus, Rhodobaenus, Stenommatus, Trochorhopalus

f. 

Lacks air tubes

Cyrtotrachelus, Dynamis [13], Rhynchophorus, Sipalinus#* see [12], Yuccaborus* (perhaps a separate state is warranted to accommodate the uniquely shaped spiracles (rounded, non-slit like orifice with small, non-scalloped airtubes) present in Yuccaborus and perhaps Sipalinus and Cyrtotrachelus.)

g. 

Spiracles functionally absent, vestigial

Eucalandra#, Sipalinus#*

Not included: Dryophthoroides, Rhinostomus

3.1.4. Abdomen

1. Functional spiracles of segments I-VII (Figure 11)

a. 

Prominent and all sub-equal in size

Cactophagus, Diathetes, Diocalandra, Eucalandra, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Nassophasis, Odoiporus, Paramasius, Poteriophorus, Rhabdoscelus, Phacecorynes, Rhodobaenus, Scyphophorus, Sitophilus, Sparganobasis, Sphenophorus, Temnoschoita, Trigonotarsus, Tryphetus

b. 

Very small

Cosmopolites*, Myocalandra*, Xerodermus* [11], Sipalinus (Gardner [12] states these are present on all segments, however, spiracles are usually very difficult to observe and may be misinterpreted as “e”.) # [12]

c. 

Present only on VII

Dryophthoroides [12], Nephius (=Anius)

d. 

Present only on I and VII

Stenommatus

e. 

Present, but II, III, and IV reduced in size by about half

Trochorhopalus

f. 

None discernable, absent

Cyrtotrachelus, Cosmopolites*, Dryophthorus, Polytus, Dynamis, Myocalandra* (may be interpreted as being absent), Rhynchophorus, Xerodermus [12], Yuccaborus

Not included: Rhinostomus

2. Abdominal segment VIII (Figure 12)

a. 

With a pair of digitate projections

Dryophthoroides [12], Dryophthorus (reduced), Mesocordylus (probably) (reduced), Nephius (=Anius), Sipalinus, Xerodermus [11,12], Yuccaborus

b. 

Without a pair of digitate projections

Cactophagus, Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra, Dynamis [13], Eucalandra, Eugnoristus, Foveolus, Metamasius, Myocalandra, Nassophasis, Odoiporus, Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sitophilus, Sparganobasis, Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus

Not included: Rhinostomus

3. Posterior margin of abdominal segment IX (Figure 13)

a. 

Without a pair of projections, may be broad and truncate

Cactophagus, Cosmopolites, Cyrtotrachelus, Diocalandra, Eucalandra, Eugnoristus, Foveolus, Metamasius, Myocalandra, Nassophasis, Odoiporus, Paramasius, Polytus, Poteriophorus, Rhabdoscelus, Rhynchophorus, Sitophilus, Sparganobasis, Sphenophorus, Temnoschoita, Trochorhopalus, Tryphetus

b. 

With 1 pair of digitate projections

Diathetes, Dryophthorus, Dryophthoroides [12], Phacecorynes, Rhodobaenus, Scyphophorus, Stenommatus, Trigonotarsus, Xerodermus [11,12], Yuccaborus

c. 

With 2 pairs of digitate projections

Mesocordylus (probably), Nephius (=Anius), Sipalinus

Not included: Dynamis, Rhinostomus

4. Shape of posterior abdominal digitate projections of segment IX (Figure 14)

a. 

Not applicable

Cactophagus, Cosmopolites, Cyrtotrachelus, Diathetes* (may be misinterpreted as this), Diocalandra, Eucalandra, Eugnoristus, Foveolus, Metamasius, Myocalandra, Nassophasis, Odoiporus, Paramasius, Polytus, Poteriophorus, Rhabdoscelus, Rhynchophorus, Sitophilus, Sparganobasis, Sphenophorus, Temnoschoita, Trochorhopalus, Tryphetus

b. 

Short and bluntly conical

Diathetes*, Rhodobaenus, Trigonotarsus

c. 

1.5 to 2× longer than wide (long and broad; reference widest section)

Dryophthorus, Dryophthoroides [12], Mesocordylus (probably), Nephius (=Anius), Phacecorynes, Scyphophorus, Sipalinus, Stenommatus, Xerodermus [11,12], Yuccaborus

Not included: Dynamis, Rhinostomus

3.1.5. Labrum/Eipharynx

1. Shape of labral seta 2 (lms2) (Figure 15)

a. 

Entire

Cactophagus, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthorus, Eugnoristus, Mesocordylus (probably), Metamasius*, Myocalandra, Nassophasis, Nephius (=Anius), Paramasius Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sitophilus, Sphenophorus, Stenommatus, Temnoschoita*, Trigonotarsus Trochorhopalus, Tryphetus, Yuccaborus

a. 

Branched (at least 1)

Cosmopolites, Eucalandra, Foveolus, Metamasius hemipterus*, Odoiporus, Temnoschoita*

Not included: Dryophthoroides, Dynamis, Rhinostomus, Sparganobasis (broken), Xerodermus

2. Peg-like pore basally on labrum (Figure 16)

a. 

Absent

Cosmopolites, Dryophthorus, Nassophasis#, Sitophilus*, Sphenophorus#*, Stenommatus

b/c. 

Single medially/submedially

Cactophagus (Right), Diocalandra (Medially), Eucalandra (Left)#*, Eugnoristus (L), Foveolus (L), Mesocordylus (probably) (M), Metamasius (M), Myocalandra (M), Nephius (=Anius)#, Paramasius (R/L), Phacecorynes (R), Polytus (M), Poteriophorus (R), Rhabdoscelus (R), Rhodobaenus (R), Sitophilus oryzae*(Medial/L), Sparganobasis (L), Temnoschoita (R), Trochorhopalus (M, slight R), Tryphetus (M)

d. 

Two submedially

Cyrtotrachelus, Diathetes, Eucalandra#*, Odoiporus, Rhynchophorus, Scyphophorus, Sipalinus, Sphenophorus* maidis, Trigonotarsus, Yuccaborus

Not included: Dryophthoroides, Xerodermus

3. Shape of epipharynx (Figure 17)

a. 

Sub-rectangular, margin evenly rounded or moderately to weakly produced medially

Cactophagus, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Dynamis [13], Eucalandra, Foveolus, Mesocordylus (probably), Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Poteriophorus, Rhabdoscelus#*, Rhinostomus, Rhynchophorus, Scyphophorus, Sipalinus, Sitophilus, Sparganobasis, Sphenophorus, Stenommatus, Trigonotarsus (medially emarginated), Trochorhopalus, Tryphetus, Xerodermus* ([11], p. 41) “Labrum strongly transverse, anterior margin trilobed, posterior margin extended medially.”), Yuccaborus

b. 

Sub-rectangular, margin truncate

Eugnoristus, Metamasius, Rhabdoscelus#*, Rhodobaenus, Temnoschoita

c. 

Sub-quadrate, markedly produced medially

Cosmopolites, Polytus

4. Lateral asperites/setae on epipharynx (Figure 18)

a. 

Absent

Diocalandra, Dryophthoroides [12], Dryophthorus, Myocalandra, Polytus, Sitophilus, Stenommatus, Tryphetus

b. 

Present

Cactophagus, Cosmopolites, Cyrtotrachelus (present basolaterally), Diathetes, Eucalandra, Eugnoristus, Foveolus, Mesocordylus (probably) (present basolaterally), Metamasius, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Poteriophorus, Rhabdoscelus, Rhinostomus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sparganobasis, Sphenophorus, Temnoschoita, Trigonotarsus, Trochorhopalus, Yuccaborus

Not included: Dynamis, Xerodermus

5. Modification of lateral setae on epipharynx (Figure 19)

a. 

Setae absent

Diocalandra, Dryophthoroides [12], Dryophthorus, Myocalandra, Polytus, Sitophilus, Stenommatus, Tryphetus

b. 

Not modified (straight, tapering)

Cosmopolites*, Cyrtotrachelus, Diathetes, Eucalandra, Mesocordylus (probably), Metamasius, Rhinostomus, Sipalinus, Sphenophorus*, Trigonotarsus, Yuccaborus* (on one side)

c. 

Twisted

Nephius (=Anius)

d. 

Curved mesally

Foveolus* (anteriorly), Paramasius, Trochorhopalus (with rounded asperites medially)

e. 

Asperites throughout

Eugnoristus, Poteriophorus, Rhabdoscelus

f. 

Asprites distally or medially, setose proximally (and laterally)

Cactophagus, Cosmopolites*, Foveolus*, Nassophasis, Odoiporus, Phacecorynes, Rhodobaenus, Rhynchophorus, Scyphophorus, Sparganobasis, Sphenophorus*, Temnoschoita, Yuccaborus*

Not included: Dynamis, Xerodermus

6. Distribution of lateral microsetae/asperites of epipharynx (Figure 20)

a. 

Setae absent

Diocalandra, Dryophthoroides [12], Dryophthorus, Myocalandra, Polytus, Sitophilus, Stenommatus, Tryphetus

b. 

1/3–1/4 distal length of labral rods

Eucalandra, Eugnoristus, Rhabdoscelus

c/d. 

Variously patterned, entire length or between 1/2–2/3 distal length of labral rods

Cactophagus, Cosmopolites, Foveolus, Metamasius, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Poteriophorus, Rhinostomus, Rhodobaenus, Rhynchophorus, Sparganobasis, Sphenophorus, Temnoschoita, Trochorhopalus

e. 

Throughout area 2/3 or less proximal length of labral rods

Cyrtotrachelus, Diathetes, Mesocordylus (probably), Scyphophorus, Sipalinus, Trigonotarsus#, Yuccaborus

Not included: Dynamis, Xerodermus

7. Lateral microsetae/asperites of epipharynx (Rhynchophorus and Cyrtotrachelus have large setae on the lateral margin) (Figure 21)

a. 

Setae absent

Diocalandra, Dryophthoroides [12], Dryophthorus, Myocalandra, Polytus, Sitophilus, Stenommatus, Temnoschoita, Tryphetus

b. 

Not reaching lateral margin of labrum

Cactophagus, Cyrtotrachelus, Eucalandra, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Paramasius, Poteriophorus, Rhabdoscelus Rhodobaenus, Rhynchophorus, Sphenophorus, Trochorhopalus, Yuccaborus

c. 

Reaching lateral margin of labrum

Cosmopolites, Diathetes, Nassophasis, Nephius (=Anius), Odoiporus, Phacecorynes, Rhinostomus, Scyphophorus, Sipalinus (minimally), Sparganobasis, Trigonotarsus

Not included: Dynamis, Xerodermus

8. Mesal asperites on epipharynx (Figure 22)

a. 

Absent

Sitophilus, Tryphetus

b. 

Present over labral rods

Eucalandra

c. 

Present medially

Cactophagus, Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhinostomus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sparganobasis, Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Yuccaborus

Not included: Dynamis, Xerodermus

9. Modification of mesal asperites of epipharynx (Figure 23)

a. 

Asperites absent

Sitophilus, Tryphetus

b. 

Setae only

Cosmopolites*, Cyrtotrachelus, Sphenophorus

c. 

Asperites only

Cactophagus, Cosmopolites*, Diathetes, Diocalandra, Dryophthorus, Eugnoristus, Mesocordylus (probably), Myocalandra, Odoiporus, Paramasius, Phacecorynes, Poteriophorus, Rhinostomus, Rhodobaenus, Sipalinus, Sparganobasis, Stenommatus*, Trochorhopalus (possibly a few setae)

d. 

Setae and asperites

Eucalandra, Foveolus, Metamasius, Nassophasis, Nephius (=Anius) (rounded asperites), Polytus, Rhabdoscelus, Rhynchophorus, Scyphophorus, Stenommatus*, Temnoschoita, Trigonotarsus, Yuccaborus

Not included: Dynamis, Dryophthoroides, Xerodermus (([11], p. 41) “…between the posteriorly conjoined rods is a pair of short setae and numerous skin points.”) (maybe “a”)

10. Orientation/placement of mesal asperites of epipharynx (Figure 24)

a. 

Asperites absent or on labral rods

Eucalandra, Sitophilus, Tryphetus

b. 

Forming a well defined elongate, mesal glabrous area

Foveolus*, Metamasius, Nassophasis, Rhinostomus, Rhodobaenus, Sphenophorus*

c. 

Forming a well defined subrectangular, mesal glabrous area

Foveolus* (could be interpreted as “b”), Paramasius, Temnoschoita

d. 

Glabrous mesal area, but loosely defined by asperites

Cyrtotrachelus, Diocalandra, Myocalandra, Nephius (=Anius), Phacecorynes, Rhynchophorus, Sipalinus, Sphenophorus*, Stenommatus

e. 

Without mesal glabrous area (between asperites)

Cactophagus, Cosmopolites, Diathetes, Dryophthoroides [12], Dryophthorus, Eugnoristus, Mesocordylus (probably), Odoiporus, Polytus, Poteriophorus, Rhabdoscelus, Scyphophorus, Sparganobasis, Trigonotarsus, Trochorhopalus, Yuccaborus

Not included: Dynamis, Xerodermus

11. Number of anterolateral epipharyngeal setae (als) (Figure 25)

a. 

2 on each side

Sitophilus, Tryphetus

b. 

3 on each side

Cactophagus, Cosmopolites, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Eucalandra, Eugnoristus, F7veolus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Scyphophorus, Sipalinus* (on one side, but probably unusual), Sparganobasis, Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Xerodermus [11]

c. 

4 on each side

Sipalinus*, Yuccaborus*

d. 

5 on each side

Yuccaborus*

e. 

10–11 on each side

Dynamis [13], Rhinostomus (10), Rhynchophorus (11)

f. 

At least 14 on each side

Cyrtotrachelus

12. Shape of anterolateral epipharyngeal setae (als 1, 2, 3) (Figure 26)

a. 

Tapering to apex

Cactophagus, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus (sometimes subapically expanded before tapering), Sitophilus, Sphenophorus*, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus, Xerodermus [11]

b. 

Bifurcate

Cosmopolites, Eucalandra, Eugnoristus, Foveolus (als1 bifurcate, als2 trifurcate), Odoiporus, Sphenophorus*

c. 

Deeply trifurcate, multifurcate (tufted)

Rhinostomus, Sipalinus, Yuccaborus

Not included: Dynamis, Sparganobasis (broken/ equally weathered?)

13. Shape of anteromedian epipharyngeal seta 1 (ams1) (Figure 27)

a. 

Entire

Cactophagus, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Mesocordylus (probably), Myocalandra, Nephius (=Anius), Phacecorynes, Polytus, Rhodobaenus, Rhynchophorus, Sitophilus, Sphenophorus*, Stenommatus, Trigonotarsus#, Tryphetus, Xerodermus [11]

a. 

Bifurcate

Cosmopolites*, Eucalandra, Eugnoristus, Metamasius, Nassophasis, Paramasius, Poteriophorus*, Rhabdoscelus, Scyphophorus*, Sphenophorus*, Temnoschoita, Trochorhopalus

c. 

Trifurcate (largely)

Cosmopolites*, Foveolus* (could be interpreted as “c”), Odoiporus, Poteriophorus*, Scyphophorus*, Sipalinus

d. 

Multifurcate, tufted

Foveolus*, Rhinostomus, Yuccaborus

Not included: Dynamis, Sparganobasis (broken/weathered all equally?)

14. Shape of anteromedian epipharyngeal seta 2 (ams2) (Figure 28)

a. 

Entire

Cactophagus, Cosmopolites*, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Mesocordylus (probably), Myocalandra, Nassophasis, Nephius (=Anius), Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sitophilus, Sphenophorus, Stenommatus, Trigonotarsus (but could be broken), Trochorhopalus, Tryphetus, Xerodermus [11]

b. 

Bifurcate

Cosmopolites*, Eucalandra, Eugnoristus, Foveolus, Metamasius, Odoiporus, Sipalinus, Temnoschoita

c. 

Tufted (deeply furcate)

Rhinostomus, Yuccaborus

Not included: Dynamis, Sparganobasis (broken/weathered all equally?)

15. Relative length of ams1 and ams2 (Figure 29)

a. 

Sub-equal

Cactophagus, Diocalandra, Dryophthoroides [12], Dryophthorus, Eucalandra, Eugnoristus*, Foveolus, Mesocordylus (probably), Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Polytus, Poteriophorus, Rhabdoscelus, Rhinostomus, Scyphophorus*, Sipalinus, Sitophilus, Sphenophorus, Stenommatus#, Trochorhopalus, Tryphetus, Yuccaborus

b. 

ams1 approximately twice as long as ams2

Cyrtotrachelus, Diathetes, Eugnoristus*, Phacecorynes, Rhynchophorus, Scyphophorus*

c. 

ams1 approximately 1/3 longer than ams2

Cosmopolites, Metamasius, Rhodobaenus, Temnoschoita

Not included: Sparganobasis (broken/weathered), Trigonotarsus (broken/weathered; maybe b/c), Xerodermus

16. Position of median epipharyngeal setae 3 (mes3) (Figure 30)

a. 

mes3 anterad on margin between 2 ams pairs; linear (this interpretation gives the appearance of 6 ams)

Cactophagus, Eucalandra, Foveolus, Metamasius, Myocalandra, Nassophasis, Paramasius, Phacecorynes, Rhabdoscelus, Rhodobaenus, Sipalinus, Sitophilus, Sphenophorus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus

b. 

mes3 proximal and almost directly in front of ams1; not linear

Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus#, Eugnoristus, Mesocordylus (probably), Nephius (=Anius), Odoiporus, Polytus, Poteriophorus, Rhynchophorus, Scyphophorus, Sparganobasis, Stenommatus, Xerodermus [12], Yuccaborus

c. 

mes3 proximal and almost directly in front of ams2; not linear

Rhinostomus

17. Minute setae apically on labrum/epipharynx (Figure 31)

a. 

Absent

Cactophagus, Cosmopolites, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Eucalandra, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius*, Myocalandra, Nassophasis, Odoiporus, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhinostomus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sitophilus, Sparganobasis, Sphenophorus pontederiae*, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus, Yuccaborus

b. 

Present

Cyrtotrachelus, Metamasius*, Nephius (=Anius), Paramasius, Sphenophorus*

Not included: Dynamis, Xerodermus

18. Short setae at the base of ams1, ams2, and mes3 (Figure 32)

a. 

Absent

Cactophagus, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Eucalandra, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Myocalandra, Nephius (=Anius), Odoiporus, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhinostomus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sitophilus, Sparganobasis, Sphenophorus maidis*, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus, Yuccaborus

b. 

Present

Cosmopolites, Cyrtotrachelus, Nassophasis, Paramasius, Sphenophorus pontederiae*

Not included: Dynamis, Xerodermus

19. Shape of mes3 apically (Figure 33)

a. 

Entire

Cactophagus, Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthorus, Mesocordylus (probably), Metamasius, Myocalandra, Nephius (=Anius), Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sitophilus, Sphenophorus*, Stenommatus, Trochorhopalus, Tryphetus, Xerodermus [11]

b. 

Bifurcate

Eucalandra, Eugnoristus, Foveolus, Nassophasis, Sphenophorus*, Temnoschoita

c. 

Trifurcate

Odoiporus, Sipalinus

d. 

Tufted

Rhinostomus, Yuccaborus

Not included: Dynamis, Sparganobasis (broken/weathered all equally?), Trigonotarsus (broken, weathered, maybe “a”)

20. Condition of mes1 (Figure 34)

a. 

Present, unmodified

Cactophagus, Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Eucalandra, Eugnoristus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhinostomus, Rhodobaenus, Rhynchophorus*, Scyphophorus, Sipalinus (very lightly sclerotized), Sitophilus, Sparganobasis, Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus, Xerodermus [11]

b. 

Present, minute (approximately 1/4 size of mes2)

Odoiporus, Rhynchophorus*

c. 

Trifurcate (tufted)

Foveolus (shallow), Yuccaborus

Not included: Dynamis

3.1.6. Mandibles (Orientation of Mandibles on a Slide Preparation May Obscure Some of the Characters)

1. Number of incisor cusps of mandible (Figure 35)

a. 

Single

Cactophagus, Eucalandra, Eugnoristus, Nephius (=Anius), Poteriophorus, Rhabdoscelus, Scyphophorus, Sipalinus#, Sitophilus granarius, Sitophilus linearis, Sparganobasis (with sub-apical lobe), Sphenophorus, Trigonotarsus, Yuccaborus

b. 

Bidentate

Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthoroides [12], Foveolus, Mesocordylus (probably), Myocalandra, Nassophasis, Odoiporus, Paramasius, Phacecorynes, Rhodobaenus, Rhynchophorus, Stenommatus, Temnoschoita, Trochorhopalus#, Tryphetus, Xerodermus [11]

c. 

Tridentate

Polytus

Not included: Dryophthorus, Metamasius, Rhinostomus

2. Internal edge with elongate concavity (Figure 36)

a. 

Absent

Cactophagus, Cyrtotrachelus, Dryophthorus, Eucalandra, Myocalandra, Nassophasis, Nephius (=Anius), Poteriophorus, Rhynchophorus, Scyphophorus, Sitophilus granarius, Sitophilus linearis, Sparganobasis, Sphenophorus, Temnoschoita, Trigonotarsus, Trochorhopalus, Yuccaborus

b. 

Present

Cosmopolites, Diathetes (apparently doble), Diocalandra, Eugnoristus, Foveolus, Mesocordylus#, Odoiporus, Paramasius, Phacecorynes, Polytus, Rhabdoscelus, Rhodobaenus, Stenommatus

Not included: Dryophthoroides, Dynamis, Metamasius, Sipalinus, Rhinostomus, Xerodermus

3. Pair of deltoid projections at base of concavity (Figure 37)

a. 

Absent

Cactophagus, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthorus, Eucalandra, Eugnoristus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Paramasius, Phacecorynes, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sitophilus, Sparganobasis, Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus, Yuccaborus

b. 

Present

Cosmopolites, Foveolus, Odoiporus, Polytus

Not included: Dryophthoroides, Dynamis, Rhinostomus, Xerodermus

4. Granular area on subapical surface of mandible (Figure 38)

a. 

Absent

Cactophagus, Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra, Eucalandra, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sitophilus*, Sparganobasis, Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus

b. 

Present

Dryophthorus, Sitophilus* granarius, Yuccaborus (basally, reduced)

Not included: Dryophthoroides, Dynamis, Rhinostomus, Xerodermus

3.1.7. Hypopharynx

1. Setation of lateral lobes of hypopharynx (Figure 39)

a. 

Reduced setation

Diocalandra*, Dryophthorus, Eucalandra#, Eugnoristus#, Myocalandra, Sitophilus#, Stenommatus, Tryphetus#

b. 

Pubescent

Cactophagus, Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra*, Foveolus, Mesocordylus (probably), Metamasius, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sparganobasis, Sphenophorus, Temnoschoita, Trigonotarsus, Trochorhopalus, Yuccaborus

Not included: Dryophthoroides, Rhinostomus, Xerodermus

2. Location of setae on hypopharynx (Figure 40)

a. 

Laterad, medially glabrous

Cyrtotrachelus, Diocalandra, Dryophthorus, Mesocordylus (probably), Myocalandra, Nassophasis, Nephius (=Anius)*, Phacecorynes, Rhodobaenus, Sitophilus, Sphenophorus*, Stenommatus, Tryphetus

b. 

Laterad with scattered medial setae

Cosmopolites, Foveolus, Nephius (=Anius)*, Polytus

c. 

Covering anterior margin not extending beyond length of mala

Eugnoristus#, Temnoschoita

d. 

Covering anterior margin and extending posterad beyond mala, usually in a narrow pubescent lateral strip resulting in a glabrous medial area

Cactophagus, Diathetes, Eucalandra, Metamasius, Odoiporus, Paramasius, Poteriophorus, Rhabdoscelus, Rhynchophorus, Scyphophorus, Sipalinus, Sparganobasis#, Sphenophorus*, Trigonotarsus, Trochorhopalus, Yuccaborus

Not included: Dryophthoroides, Dynamis, Rhinostomus, Xerodermus

3.1.8. Maxilla

1. Shape of mala (Figure 41)

a. 

Digitate (anterior margin rounded)

Cactophagus, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Eucalandra, Mesocordylus (probably), Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Poteriophorus, Rhabdoscelus, Scyphophorus, Sparganobasis, Sphenophorus* (but could be interpreted as “b” by some), Temnoschoita, Trochorhopalus, Tryphetus

b. 

Subquadrate (anterior margin angled but distinctly truncate)

Cosmopolites, Eugnoristus, Metamasius, Polytus, Rhodobaenus, Sipalinus, Sitophilus, Sphenophorus* (but could be interpreted as “a” by some), Yuccaborus

c. 

Quadrate (anterior margin truncate)

Foveolus, Rhynchophorus, Stenommatus, Trigonotarsus

Not included: Xerodermus, Rhinostomus

2. Asperites/microsetae on dorsal mala (Figure 42)

a. 

None discernable

Cyrtotrachelus, Dryophthoroides [12], Dryophthorus, Mesocordylus (probably), Myocalandra, Rhabdoscelus, Sitophilus, Stenommatus

b. 

Present but not between dms

Diocalandra, Nassophasis, Phacecorynes, Rhodobaenus *(may be misinterpreted as “c”), Rhynchophorus, Sipalinus, Trochorhopalus, Tryphetus

c. 

Present at base of and between dms

Cactophagus, Cosmopolites (asperites mostly), Diathetes (dms 3–8), Eucalandra, Eugnoristus, Foveolus (dms 2–8), Metamasius, Nephius (=Anius), Odoiporus (copious amounts), Paramasius (dms 1–8), Polytus, Poteriophorus, Rhodobaenus* (but setae not asperites), Scyphophorus, Sparganobasis (only at base of dms 2–8), Sphenophorus, Temnoschoita, Trigonotarsus, Yuccaborus

d. 

Present between dms 4–8 and as a distinct rounded area of microsetae (dms 1–3)

Trigonotarsus

Not included: Rhinostomus, Xerodermus

3. Asperites/microsetae on stipes distally (base of maxillary palp), dorsal view (Figure 43)

a. 

None discernable

Dryophthoroides [12], Dryophthorus, Foveolus (but asperites at base of mala), Metamasius, Myocalandra, Phacecorynes, Polytus, Rhabdoscelus, Sipalinus, Sitophilus, Sphenophorus*, Stenommatus, Tryphetus

b. 

Asperites present

Cactophagus, Cosmopolites, Diathetes, Diocalandra, Eucalandra, Eugnoristus, Mesocordylus (probably) (serrate), Nassophasis, Odoiporus, Paramasius, Poteriophorus, Rhodobaenus (very fine), Rhynchophorus, Scyphophorus, Sparganobasis, Sphenophorus* (very fine), Temnoschoita, Trigonotarsus, Trochorhopalus, Yuccaborus

c. 

Elongate and thin setae present

Nephius (=Anius)

d. 

Elongate and stout setae present

Cyrtotrachelus

Not included: Dynamis, Rhinostomus, Xerodermus

4. Arrangement of dorsal malar setae (dms) (Figure 44)

a. 

Regularly aligned in single row (dms 7,8 may sometimes be more lateral, but always in a single file)

Cactophagus (dms 7,8 laterad), Cosmopolites, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Eucalandra (dms 7,8 somewhat distant from dms 3–8), Eugnoristus, Foveolus (dms 7,8 somewhat distant from dms 1–6), Mesocordylus (probably), Metamasius (dms 7,8 somewhat distant from dms 3–8), Myocalandra, Nassophasis (dms 7,8 somewhat distant from dms 1–6), Nephius (=Anius), Odoiporus, Paramasius (dms 7,8 somewhat distant from dms 1–6), Phacecorynes, Polytus, Poteriophorus (dms 7,8 somewhat distant from dms 1–6), Rhabodscelus (dms 7,8 somewhat distant from dms 1–6), Rhodobaenus (dms 7,8 somewhat distant from dms 1–6), Scyphophorus (dms 7,8 somewhat distant from dms 1–6), Sipalinus, Sitophilus oryzae#(some Sitophilus may have dms irregularly distributed), Sparganobasis, Sphenophorus (dms 7,8 somewhat distant from dms 1–6), Stenommatus, Temnoschoita (dms 7,8 somewhat distant from dms 1–6), Trochorhopalus, Tryphetus, Xerodermus [11], Yuccaborus

b. 

Regularly distributed medially, proximally somewhat clumped

Cyrtotrachelus, Rhynchophorus, Trigonotarsus#

Not included: Dynamis, Rhinostomus

5. Number of dorsal malar setae (dms) (Figure 45)

a. 

Less than five (5)

Sitophilus (but unclear)

b. 

Six (6)

Dryophthoroides# ([12], (p. 253) “…row of about six fissile setae and one or two simple setae.”), Dryophthorus, Eugnoristus* (but not entirely clear), Tryphetus#*, Xerodermus [11]

c. 

Seven (7)

Myocalandra

d. 

Seven (7) (with a small pore)

Stenommatus

e. 

Eight (8)

Cactophagus, Cosmopolites, Diathetes, Diocalandra, Eucalandra, Eugnoristus*, Foveolus, Mesocordylus (probably), Metamasius, Nassophasis, Nephius (=Anius), Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Scyphophorus, Sparganobasis, Sphenophorus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus#*

f. 

Ten (10)

Odoiporus (10–11), Yuccaborus

g. 

Fourteen (14)

Rhynchophorus

h. 

Fifteen (15)

Sipalinus

i. 

More than 30

Cyrtotrachelus

Not included: Dynamis, Rhinostomus

6. Shape of dorsal malar setae (dms) (if at least one is branching, select b, see next couplet) (Figure 46)

a. 

Entire

Cactophagus, Cyrtotrachelus (possibly some distally may be superficially branched), Phacecorynes, Rhodobaenus, Rhynchophorus (occasional bifurcate seta), Sitophilus, Tryphetus

b. 

Branching

Cosmopolites, Diathetes, Diocalandra, Dryophthoroides [12], Dryophthorus, Eucalandra, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Polytus, Poteriophorus, Rhabdoscelus, Scyphophorus, Sipalinus, Sparganobasis, Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Xerodermus [11], Yuccaborus (tufted)

Not included: Dynamis, Rhinostomus

7. Progression of branching of dorsal malar setae (dms) (this is a more generalized version of character 8 below) (Figure 47)

a. 

Entire, not branching

Cactophagus, Cyrtotrachelus (possibly some distally may be superficially branched), Phacecorynes, Rhodobaenus, Rhynchophorus (occasional bifurcate seta), Sitophilus, Tryphetus

b. 

All dms equally branching

Cosmopolites, Diocalandra, Eugnoristus, Foveolus, Nassophasis, Odoiporus, Paramasius*, Polytus, Scyphophorus, Sipalinus, Temnoschoita, Yuccaborus

c. 

Branching dms distally decreasing

Diathetes (dms 3–8 branching), Dryophthoroides [12], Dryophthorus, Mesocordylus (probably), Myocalandra, Poteriophorus, Rhabdoscelus, Stenommatus, Trigonotarsus

d. 

Branching dms distally increased

Eucalandra, Metamasius, Nephius (=Anius), Paramasius*, Sparganobasis (dms 8 bifurcate, others trifurcate?), Sphenophorus, Trochorhopalus

Not included: Dynamis, Rhinostomus, Xerodermus

8. Variation of branching of dms (slight plasticity may exist and should be considered; this couplet is a more complicated (less generalized) version of couplets #6, 7 above) (Figure 48)

a. 

Not branching

Cactophagus, Cyrtotrachelus (distal setae may be superficially branched), Phacecorynes, Rhodobaenus, Rhynchophorus (occasional bifurcate seta), Sitophilus, Tryphetus

b. 

All bifurcate

Cosmopolites, Diocalandra, Eugnoristus, Paramasius*, Polytus, Sparganobasis

c. 

Some dms entire, others bifurcate

Diathetes [dms 1–2 entire, dms 3–8 bifurcate (shallow)], Dryophthorus (dms 2–6 bifurcate, dms 1 entire), Eucalandra (dms 1–6 bifurcate, dms 7, dms 8 entire), Mesocordylus (probably) (dms 1–5 entire, dms 6–8 bifurcate), Metamasius (dms 1–6 bifurcate, dms 7, dms 8 entire; sometimes dms 7 or 8 may be bifurcate), Myocalandra (dms 1–6 entire, dms 7 bifurcate), Nephius (=Anius) (dms 1–6 bifurcate, dms 7, dms 8 entire), Paramasius* (dms 1–7 bifurcate, dms 8 enitre), Sphenophorus (dms 1–6 bifurcate, dms 7, dms 8 entire), Stenommatus (dms 1 entire, dms 2–7 bifurcate), Trochorhopalus (dms 1–6 bifurcate, dms 7, dms 8 entire)

d. 

Some dms bifurcate, others multifurcate

Dryophthoroides#* (([12], p. 253) “…row of about six fissile setae and one or two simple setae.”) [12], Poteriophorus (dms 1–3 bifurcate, dms 4–8 tufted, shallow and multi-furcate), Rhabdoscelus (dms 1–2, 8 bifurcate, dms 3–7 multifurcate), Scyphophorus [dms 1–6 bifurcate, dms 7, 8 tufted (deeply and multi-furcate)], Trigonotarsus (dms 1–5 bifurcate, dms 6–8 multifurcate)

e. 

All tufted (shallow and multi-furcate)

Dryophthoroides#* [12], Foveolus (with long setae at base), Nassophasis, Odoiporus, Temnoschoita

f. 

All tufted (deeply and multi-furcate)

Sipalinus, Yuccaborus

Not included: Dynamis, Rhinostomus, Xerodermus ([11], (p. 41) “…mala with several branched setae, six of them in a longitudinal row not extending far from apex.”)

9. Ventral malar setae (vms) (Figure 49)

a. 

Unbranched

Cactopahgus, Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthorus, Eucalandra, Mesocordylus (probably), Myocalandra, Nephius (=Anius), Paramasius, Phacecorynes, Rhodobaenus, Rhynchophorus, Scyphophorus, Sitophilus, Sparganobasis Sphenophorus, Stenommatus, Tryphetus

b. 

One (1) branched, remainder unbranched

Polytus, Rhabdoscelus, Trigonotarsus#

c. 

Two (2) branched

Foveolus#*, Eugnoristus, Metamasius, Sipalinus, Trochorhopalus

d. 

More than two branched

Foveolus#*, Nassophasis, Odoiporus (3), Poteriophorus, Temnoschoita, Yuccaborus (at least 3)

Not included: Dryophthoroides, Dynamis, Rhinostomus, Xerodermus

10. Pair of short, contiguous vms4 and vms3 (bilobed vms3?) (Figure 50)

a. 

Absent

Cactopahgus, Diathetes, Diocalandra, Dryophthorus, Eugnoristus, Foveolus#*, Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus (apparently very small one present, but unclear), Trochorhopalus, Tryphetus, Yuccaborus

b. 

Present

Cosmopolites, Cyrtotrachelus, Eucalandra, Foveolus#*, Mesocordylus (probably), Polytus, Sitophilus, Sparganobasis (bilobed vms3?)

Not included: Dryophthoroides, Dynamis, Rhinostomus, Xerodermus

3.1.9. Labium

1. Ligula with copious apical setation (Figure 51)

a. 

Absent

Cactopahgus, Cosmopolites, Cyrtotrachelus, Diathetes, Eucalandra, Mesocordylus (probably), Nassophasis, Odoiporus, Phacecorynes, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sitophilus, Sparganobasis, Trigonotarsus, Tryphetus, Yuccaborus

b. 

Present

Diocalandra, Dryophthorus (small amounts of setae), Eugnoristus, Foveolus, Metamasius, Myocalandra, Nephius (=Anius), Paramasius, Polytus, Sphenophorus, Stenommatus (reduced), Temnoschoita, Trochorhopalus (reduced), Xerodermus [11]

Not included: Dryophthoroides, Dynamis, Rhinostomus

2. Ligular seta 1 (lgs1) (Figure 52)

a. 

Entire

Cactopahgus, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthorus, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Paramasius, Poteriophorus, Phacecorynes, Polytus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sitophilus, Sparganobasis (broken/weathered), Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus, Xerodermus [11]

b. 

Branched

Cosmopolites, Eucalandra, Odoiporus

c. 

Tufted

Yuccaborus

Not included: Dryophthoroides, Dynamis, Rhinostomus, Sipalinus

3. Position of postmental setae (pms1, 2, 3) (Figure 53)

a. 

Linear

Dryophthorus, Mesocordylus (probably), Stenommatus

b. 

Not linear

Cactophagus, Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra, Eucalandra, Eugnoristus, Foveolus, Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sitophilus, Sparganobasis, Sphenophorus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus, Yuccaborus

Not included: Dryophthoroides, Dynamis, Rhinostomus, Xerodermus

4. Second labial palpomere (Figure 54)

a. 

Absent/reduced

Dryophthorus, Stenommatus

b. 

Present, prominent

Cactophagus, Cosmopolites, Cyrtotrachelus, Diathetes, Diocalandra, Dryophthoroides [12], Eucalandra, Eugnoristus, Foveolus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Nephius (=Anius), Odoiporus, Paramasius, Phacecorynes, Polytus, Poteriophorus, Rhabdoscelus, Rhodobaenus, Rhynchophorus, Scyphophorus, Sipalinus, Sitophilus, Sparganobasis, Sphenophorus, Temnoschoita, Trigonotarsus, Trochorhopalus, Tryphetus, Xerodermus [11], Yuccaborus

5. Pigmentation of premental sclerite (Figure 55)

a. 

Trident

Cactophagus, Cyrtotrachelus, Diocalandra, Dryophthorus, Dryophthoroides# [12], Eucalandra, Eugnoristus (anteriorly reduced), Foveolus, Mesocordylus (probably), Metamasius, Myocalandra, Nassophasis, Paramasius, Phacecorynes, Polytus*, Poteriophorus, Rhabdoscelus, Rhynchophorus, Scyphophorus, Sitophilus, Sparganobasis, Sphenophorus, Stenommatus, Temnoschoita, Trigonotarsus#*, Trochorhopalus, Tryphetus, Xerodermus [11]

b. 

Trident, with prominent, narrow, elongate anterior extension (almost reaching apex of ligula)

Sipalinus, Trigonotarsus#*, Yuccaborus

c. 

Triangular

Cosmopolites, Polytus*, Rhodobaenus

d. 

Effaced

Diathetes, Nephius (=Anius), Odoiporus

Not included: Dynamis, Rhinostomus

4. Discussion

Fifty-two (52) fully illustrated characters of dryophthorine larvae are provided to assist in the identification of this economically important group and difficult to identify life stage. The larvae of some dryophthorine genera, such as Sipalinus, Scyphophorus, and Cosmopolites, are readily recognizable based on a combination of salient characters such as the presence of caudal digitate processes and/or the absence of functional spiracles on the abdomen. This key attempts to provide the user with the freedom to initiate the identification process from any couplet in the key. This identification tool focuses rather heavily on characters of the mouthparts.

This study includes, for the first time, information on the larva of six previously unknown genera of Dryophthorinae: Mesocordylus (probably), Foveolus, Nassophasis, Poteriophorus, Sparganobasis, Eugnoristus, and Tryphetus. In addition, the larva of the once valid genus Paramasius, now treated as a junior synonym of Metamasius, is described for the first time. Data on the larva of Paramasius will be included in ongoing phylogenetic and comparative studies to determine whether synonymy of this genus is supported.

Chaetotaxy of the body, although historically relied upon by authors to segregate the major groups within Dryophthorinae [9], was not used here because of extensive amount of missing data due to rubbing or deterioration of specimens. Furthermore, characters previously used by May [15] and Marvaldi and Morrone [6], such as the number of abdominal superimposed lobes (2, 3, or 4) were not included. Additional features that presented challenges and were not included due to difficulty assessing homology are the presence and location of the posterior accessory sensory pores (pasps) and of the sensory pores (snp).

The current comparative study of dryophthorine larvae is intended to serve as a source of data for ongoing phylogenetic analyses of the subfamily, and preliminary results suggests the presence of significant signal for understanding relationships among higher groups within Dryophthorinae. Zimmerman [21] provided the most comprehensive overview of dryophthorines to date (his Rhynchophoridae) and discussed the placement of the now tribes Stromboscerini and Dryophthirini, which Anderson [9] placed collectively under Stromboscerinae. Grebennikov [22] hypothesized Dryophthorini and Stromboscerini to be sister taxa and suggested the possible exclusion of Nephius from Stromboscerini. Study of known stromboscerine larvae Dryophthoroides, Xerodermus [11,12], and Nephius (=Anius) suggests retention of the tribe in Dryophthorinae and supports its distinction from Dryophthorini, here represented by Stenommatus and Dryophthorus. The retention of Nephius in Stromboscerini remains uncertain. These are preliminary results and a morphological and molecular phylogenetic analysis is currently underway.