Thecomyia Perty

Marinoni, Luciane, Steyskal, George C. & Knutson, Lloyd, 2003, Revision and cladistic analysis of the Neotropical Genus Thecomyia Perty (Diptera: Sciomyzidae), Zootaxa 191, pp. 1-36 : 3-6

Genus Thecomyia Perty

Thecomyia Perty, 1833: 189 [type species: Thecomyia longicornis Perty , by original designation.­ Knutson et al., 1976: 13 [Neotropical catalog].­ Knutson and Vala, 1999: 455 [character matrix].­ Vala et al., 2000: 253 [character matrix].­ Marinoni and Mathis, 2000: 191 [cladistic analysis].

Description.­General coloration: Body brown with yellow stripe laterad of scutum and vertical stripe from anepisternum to katepisternum. Body length: 7­11 mm; wing length: 6­9 mm.

Head ( Figs. 2 and 3 ): Ventral portion of head drawn into a conical rostrum; width of gena as much as 0.76 height of eye, reaching 0.97 in some females. Palpi reduced, at most represented by a few setae. Eyes very prominent. Head sutures indistinct, ptilinal fissure absent, thus area of lunule greatly exposed, fused with anterior margin of frons. Midfrontal vitta absent. No midfrontal or facial setulae. Fronto­orbital spot present; 0­1 (weak to strong) upper orbital seta; ocellar and postocellar setae lacking; inner and outer vertical setae well developed. Pedicel equal in length to first flagellomere; arista sub­basal, bearing long white hairs.

Thorax ( Fig. 4 ). Medial mesonotonal stripe simple or tripartite. 0 prosternal, pro­episternal, postpronotal, presutural, subalar, anepisternal, katatergal, katepisternal or anepimeral setae. 1­2 notopleural setae, anterior seta very small and weak; 1 supra­alar; 1 postalar; 1 weak or 0 prescutellar dorsocentral, 1 pair of scutellar. No setae around metathoracic spiracle. Pleura bare. Mesonotal suture complete. Area above hind coxae completely sclerotized. Wing infumate, not patterned; veins R4+5 and M1 not convergent apically, crossvein dm­cu straight; A1+CuA2 complete to margin; anal cell truncate; anal lobe not expanded. Fore coxa bearing a few short antero­apical setae; mid coxa with 1 well developed mid lateral seta and a few short antero­apical setae; hind coxa with posterior inner margin bare, 1 strong posterolateral seta and a few short apical setae; fore and mid trochanters with 1 moderately strong anterodorsal seta; hind trochanter densely covered with short, strong setulae ventrally; mid and hind femora with 4­8 short, strong, spinelike setae ventrally near apex; mid femur with or without small, anteromedial seta; hind femur with or without anteromedial seta; hind femur ventrally with 7­13 subapical, spinelike setae forming lines anteriorly and posteriorly; tibiae with 1 short, dorsal pre­apical seta, that of fore tibia strongest, and 3­4 short, strong apical setae posteriorly; hind tibia with 4­5 pairs of slightly stronger spinelike setae ventrally on each side at apical 1/3; hind tibia straight not arched; fore and hind tibiae on inner apical margin with a pecten (series of many fine, equally sized, short, closely spaced setulae).

Male abdomen ( Figs. 6­29). Sternite 6 asymmetrical, normally extended from mid dorsum onto left side, where it is expanded and strongly sclerotized; left spiracle 6 mid laterally at beginning of expanded portion; left spiracle 7 in sclerotized strip lying in membrane below synsternite 7+8. Synsternite 7+8 1/2­2/3 size of epandrium in lateral view. Epandrium in posterior view nearly complete, narrowly membranous below cerci; cercus small, with apico­ventral portion wide and well sclerotized. Ejaculatory apodeme wider basally than phallapodeme, with muscle attachments at base and with short, triangular piece articulated by membrane with stem. Phallapodeme straight to slightly curved distally, with process or spur on anterior surface subapically in some species. Epiphallus covering base of distiphallus. Distiphallus complex, asymmetrical, with acrophallus and associated plates either elongate and curved apically, moderately long and curved, or short with variously shaped plates or processes. Hypandrium with pair of weak, linear struts posteriorly, medial portion very broadly expanded into pair of large, ventrally projecting plates that vary in shape among the species. Anteroventral hypandrial plates projecting below surstylus in some species; a pair of narrow, archlike struts on posterior border of plates, meeting mid dorsally at apex of distiphallus. Hypandrium with margins of anteroventral plates bearing membranous projection varying in shape and size among species; bearing some sort of cilia. Gonopod fused to hypandrium. Aedeagal complex asymmetrical; anterior basiphallic process curved or cuneate and tripartite apically. Posterior and anterior surstyli articulated with well sclerotized bacilliform sclerite, which in turn articulates with epandrium and hypandrium; posterior and anterior surstyli distinct and widely separated or only the posterior well developed.

Female (Figs. 30­40). Sternites 6, 7 and 8 almost fused. With 2 spermatheca; spermathecal duct very wide and well sclerotized at junction with spermatheca; in some species with an apical digitiform projection.

Figures

FIGURES 2 ­ 5. Thecomyia mathisi: 2, head, anterolateral view; 3, head anterodorsal view. Thecomyia chrysacra Marinoni and Steyskal: 4, thorax, dorsal view; 5, abdomen, dorsal view.