Therevidae

Phycus frommeri, copyright Spencer Entomological Collection.

Belongs within: Asiloidea.
Contains: Agapophytinae, Therevinae.

The Therevidae, stiletto flies, are a group of often fast-flying flies that are predatory as larvae but not as adults. Major subgroups include the Phycinae, found in Africa and the Americas (Irwin & Lyneborg 1981).

Characters (from Irwin & Lyneborg 1981): Slender to moderately thick-bodied flies; length, excluding antennae, 2.5-15 mm. Background color light yellow to black. Head hemispherical, not depressed at vertex. Eyes dichoptic in female, holoptic in most males, usually without hairs in both sexes. Frons of female wide, reaching ocellar tubercle; frons of male usually small, acutely to broadly triangular, pruinose to bare. Three prominent ocelli set at vertex or slightly anterior to vertex. Antenna three-segmented; scape usually setose, especially ventrally; pedicel usually with ring or two of short setae; first flagellomere without setae, or with setae usually confined to basal third; stylus comprising one or two flagellomeres and a terminal or subterminal bristle, set apically or subapically on basal flagellomere. Face often pruinose; lateral area hairy or not; gena hairy or not; occiput finely pruinose; postocular setae usually present though often weak. Palpus one- or two-segmented, usually hairy and not prominent, set beside proboscis in subcranial cavity; proboscis slightly longer than palpus, usually carried within subcranial cavity. Thorax with scutum varying from nearly square to elongate rectangular when viewed from above. Scutellum prominent, often without hairs, but almost always pruinose and often tomentose. Pleuron variously pilose; upper portion usually densely pruinose. Chaetotaxy with one pair postalar setae; one to six pairs notopleural setae, or more; one or two pairs supra-alar setae; usually from zero to two pairs dorsocentral setae, but three or more in a few species; zero to three, rarely four, pairs scutellar setae. Legs usually fairly long and slender; hindleg longer than other two. Fore coxa with none to several setae on anterior surface; all femora bare to heavily setose especially postventrally, often with long scale-like pile along dorsal surface; tibiae and tarsi setulose in definite longitudinal rows; fore tibia lacking setae anteroventrally. Five tarsomeres present; first tarsomere longest; claw with two pulvilli and seta-like central empodium, or with empodium absent. Wing venation generally uniform; R1 setose or not; R4 elongate, often sinuate; cell d elongate, with M1, M2 and M3 arising from apex; CuA1 not meeting posterior margin of cell d; crossvein m-cu present; cell cup closed behind; cell m3 open or closed. Pterostigma usually well-developed. Calypter well-developed. Halter large and well-developed. Abdomen usually convex to flattened dorsally and tapering at apex, sometimes laterally compressed, always with eight well-developed pregenital segments. Fine silvery pollen often adorning abdomen. Tomentum and pile present or absent, usually longer and denser on male. Female terminalia with large conspicuous sternite 8; sternite 9, or genital fork, completely internal, with two lateral sclerites fused posteriorly to sclerotized bar containing membranous central sheath through which pass ducts of spermathecae and accessory glands; three usually unsclerotised spermathecae and two accessory glands present; tergite 8 generally unmodified; tergite 9 usually a single sclerite, generally with extended lateral margins fused to posterolateral margins of genital fork; tergite l0 always divided, often fused with tergite 9; digging-anchoring spines often present posterodorsally and anterolaterally; sternites l0 and ll (hypoproct, subanal plate) usually a single plate, usually heavily sclerotised; cerci disc-shaped. Male terminalia with sclerites forming sternite 8 and tergite 8 unmodified to narrowly constricted; tergite 9 (epandrium) acting as large covering for terminalia, often with surstyli or lateral surstylar-like lobes of various sizes and shapes; hypoproct and cerci borne apically; gonocoxites often extending as broad to narrow lobe well beyond insertion of gonostylus, usually with one or more other appendages; aedeagus consisting of a short to long variously twisted distiphallus, an elongate or vestigial dorsal aedeagal apodeme, a simple or forked ventral apodeme, and a variously shaped ejaculatory apodeme. Larva elongate, cylindrical, tapering anteriorly toward head and apex of abdomen; head small, with cranium well-sclerotised and divided into two portions; anterior portion exposed and strongly tapered anteriorly toward mouthparts; posterior portion a long apically spatulate metacephalic rod, flexibly articulated to posterior dorsal margin of anterior cranial portion and projecting into thorax; mouthparts comprising median slender tapered labrum flanked by curved pointed mandibles, and laciniae and palpi of maxillae, with elements of labium ventrally; labium consisting of large postmentum closing ventral part of cranial cavity, a fused pair of labial palpi usually bearing several pairs of setae, and prementum anteriorly; cranium exteriorly with several sensory cells both dorsally and ventrally, with antennae set in crescent-shaped cups on anterodorsal surface, with one pair of elongate dorsal setae and two pairs of elongate ventral setae, with heavily sclerotized postmentum ventrally, and dorsally with some weakly sclerotized portions called white areas; two pairs of heavy tentorial arms present internally. Thorax with pair of dorsolateral setae on each segment; anterior spiracle distinct, with two or three spiracular openings on specimens examined; abdominal segments l-8 secondarily constricted, giving appearance of two segments each, which with three thoracic segments appear as 19 segments in all; posterior spiracles on antipenultimate segment, apparently with eight spiracular openings; terminal segment ending in pair of retractable finger-like prolegs.

<==Therevidae
|–+–+–Nanexila gracilis WY01
|  |  `–+–Agapophytinae WY01
|  |     `–Therevinae WY01
|  `–+–Ectinorhynchus WY01
|     `–Taenogerella WY01
|          |–T. elizabethae WY01
|          `–T. platina WY01
`–Phycinae IL81
|–Parapherocera wilcoxi IL81
|–Schlingeria IL81
|–Ataenogera brevicornis IL81, GW09
|–Ruppellia vagabunda IL81
|–Pherocera IL81
|    |–P. albilateralis GW09
|    `–P. flavipes IL81
`–Phycus WY01
|–P. frommeri GW09
|–P. frontalis GW09
|–P. kroberi WT11
`–P. niger WY01

Therevidae incertae sedis:
Rhagiophryne bianalis BLM02
Taenogera luteola WY01, ZS10
Neodialineura WY01
Acrosathe IL81
|–A. novella WT11
`–A. pacifica IL81
Megalinga GW09
|–M. bolbocera GW09
`–M. insignata IL81
Nebritus pellucidus IL81
Litolinga acuta IL81
Pallicephala IL81
|–P. pachyceras GW09
`–P. willistoni IL81
Rhagioforma GW09
|–R. maculipennis IL81
`–R. schmidti GW09
Lyneborgia IL81
Chromolepida IL81
Eothereva simplex IL81
Arenigena semitaria GW09
Lysilinga IL81
|–L. crassiseta GW09
|–L. dolichophalla GW09
`–L. pilifrons GW09
Dialineura gorodkovi IL81
Pandivirilia bussi IL81
Ammonaios niveus IL81
Tabuda IL81
Tabudamima melanophleba IL81
Spiriverpa candidata IL81
Viriliricta IL81
Dichoglena IL81
Penniverpa GW09
|–P. epidema GW09
|–P. evani GW09
|–P. festina IL81
`–P. multisetosa GW09
Xestomyzinae GW09
|–Xestomyza IL81
`–Henicomyia hubbardii GW09
Microthereva GW09
Peralia GW09
Entesia GW09
Melanothereva GW09
Ptilotophallos GW09
Apenniverpa GW09
Pachyrrhiza GW09
Distostylus GW09
Spinalobus GW09
Insulatitan GW09
Incoxoverpa GW09
Protothereva GW09
Winthemmyia GW09
Amplisegmentum GW09
Notiothereva GW09
Nigranitida GW09
Elcaribe GW09
Argolepida GW09
Cliorismia GW09
Lindneria dicosta GW09

*Type species of generic name indicated

REFERENCES

[BLM02] Blagoderov, V. A., E. D. Lukashevich & M. B. Mostovski. 2002. Order Diptera Linné, 1758. The true flies (=Muscida Laicharting, 1781). In: Rasnitsyn, A. P., & D. L. J. Quicke (eds) History of Insects pp. 227–240. Kluwer Academic Publishers: Dordrecht.

[GW09] Gaimari, S. D., & D. W. Webb. 2009. Therevidae (stiletto flies). In: Brown, B. V., A. Borkent, J. M. Cumming, D. M. Wood, N. E. Woodley & M. A. Zumbado (eds) Manual of Central American Diptera vol. 1 pp. 633–647. NRC Research Press: Ottawa.

[IL81] Irwin, M. E., & L. Lyneborg. 1981. Therevidae. In: McAlpine, J. F., B. V. Peterson, G. E. Shewell, H. J. Teskey, J. R. Vockeroth & D. S. Wood (eds) Manual of Nearctic Diptera vol. 1 pp. 513–523. Research Branch, Agriculture Canada.

[WT11] Wiegmann, B. M., M. D. Trautwein, I. S. Winkler, N. B. Barr, J.-W. Kim, C. Lambkin, M. A. Bertone, B. K. Cassel, K. M. Bayless, A. M. Heimberg, B. M. Wheeler, K. J. Peterson, T. Pape, B. J. Sinclair, J. H. Skevington, V. Blagoderov, J. Caravas, S. N. Kutty, U. Schmidt-Ott, G. E. Kampmeier, F. C. Thompson, D. A. Grimaldi, A. T. Beckenbach, G. W. Courtney, M. Friedrich, R. Meier & D. K. Yeates. 2011. Episodic radiations in the fly tree of life. Proceedings of the National Academy of Sciences of the USA 108 (14): 5690–5695.

[WY01] Winterton, S. L., L. Yang, B. M. Wiegmann & D. K. Yeates. 2001. Phylogenetic revision of Agapophytinae subf. n. (Diptera: Therevidae) based on molecular and morphological evidence. Systematic Entomology 26: 173–211.

[ZS10] Zborowski, P., & R. Storey. 2010. A Field Guide to Insects in Australia 3rd ed. Reed New Holland: Sydney.

Last updated: 15 May 2018.

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