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Family Vermileonidae - Wormlions

Los Angeles wormlion - Vermileo opacus Los Angeles wormlion - Vermileo opacus Sierra wormlion - Vermileo comstocki Sierra wormlion - Vermileo comstocki wormlion - Vermileo opacus wormlion - Vermileo opacus Vermileo image w/ palps indicated by arrows - Vermileo comstocki - male Vermileo comstocki
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Diptera (Flies)
No Taxon (Orthorrhapha)
Infraorder Tabanomorpha
Family Vermileonidae (Wormlions)
Synonyms and other taxonomic changes
Formerly considered part of Rhagionidae
Explanation of Names
Vermileoninae Williston 1886 (see footnote here)
Vermileonidae Nagatomi 1977
2 spp. in a single genus in our area(1), ~60 spp. in 12 genera total(2)
Eyes large, hairless, dichoptic, facets equal, frons slightly narrower in male, scape longer than pedicel, flagellum with 3-8 flagellomeres and with apical 1-3 forming a slender apical or subdorsal stylus, face weakly to moderately convex, labium short or 3/4th length of body
Scutum lacking traces of transverse suture, mediotergite of postnotum large, anterior margin of anepimeron bowed, subscutellum absent or very weakly developed, posterior thoracic spiracle never with a scale-like elevation immediately behind it, scutellum small, with a flat bare disc
Legs long and slender, hind femora somewhat enlarged distally, tibial spur formula 1-2-2, first tarsomeres long, empodia pulvilliform (pulvilli and empodia reduced in the Palearctic genus Lampromyia)
C continuing around wing, strong in anal and alular area, branches of R and M diverging to apical wing margin, vein R3 strongly curved anteriorly in some, vein R5 ending beyond wing apex, branches of M joining margin far below apex of wing and without composite ‘diagonal’ vein, cells M3 and cup closed or strongly narrowed at margin, or M3 reduced, CuA2 free and ending at wing margin, anal lobe and alula undeveloped, alular incision absent, calypters small
In our area, sw. US (CO-NM-CA)(1)
Larvae make pitfall traps in dust/sand, similar to those of antlions in appearance and function(1).
Family Vermileonidae is unique among Diptera in having larvae that capture prey by constructing pitfall traps in loose soil (like antlions).
The family Vermileonidae is also interesting in terms its enigmatic place within the evolutionary and systematic context of the suborder Brachycera of Diptera. Traditionally placed as a subfamily of Rhagionidae (beginning in 1886, see footnote in Williston here), the group was given the rank of family by Nagatomi(1977), of uncertain placement (incertae sedis). Male terminalia in Vermileonidae resemble those of Therevidae in the superfamily Asiloidea, while larval mouthparts are similar to those of the superfamily Empidoidea. It has been variously placed as sister to Rhagionidae, or as its own infraorder sister to Xylophagomorpha near the base of Brachycera. It is apparently an old group...with the most recent work suggesting its the most primitive family of the infraorder Tabanomorpha.
Print References
Nagatomi, Akira (1977). Classification of the lower Brachycera (Diptera). Journal of Natural History 11(3):321-335
Nagatomi, A., C. Yang, & D. Yang. (1999). The Chinese species and the world genera of Vermileonidae (Diptera). Tropics, Monograph Series I: 1-154. (Full Text)
Nagatomi, A., T. Saigusa, H. Nagatomi, L. Lyneborg. (1991). The systematic position of the Apsilocephalidae, Rhagionempididae, Protempididae, Hilarimorphidae, Vermileonidae and some genera of Bombyliidae (Insecta, Diptera). Zool. Science 8:593-607. (Full Text)
Ovtshinnikova, O.G. (2000). Male genital musculature of Vermileonidae (Diptera, Brachycera) and systematic position of the family. Entolmologicheskoe Obozrenie 79: 513-52l.
Wheeler W.M. (1930) Demons of the dust. New York: W.W. Norton & Company.
Williston, S. W. (1886). On two new interesting genera of Leptidae. Entomologica Americana 2(6):105-108. (Full Text)
Yeates, D.K. (2002). Relationships of extant lower Brachycera (Diptera): a quantitative synthesis of morphological characters. Zoologica Scripta 31: 105-121 (Full Text...scroll down page)