Gonia Meigen, 1803

Hou, Peng, Li, Xin, Yang, Ding & Zhang, Chuntian, 2018, Taxonomic study of Gonia Meigen (Diptera: Tachinidae) from China, Zoological Systematics 43 (3), pp. 294-308 : 295-296

3.1 Genus Gonia Meigen, 1803

Gonia Meigen, 1803: 280 , subsequent designated by Sabrosky & Arnaud, 1965; Herting & Dely-Draskovits, 1993: 257; Chao et al., 1998: 1941; O’Hara et al., 2009: 108; Lee & Han, 2010: 175; Zhang et al., 2016: 406.

Type species: Gonia bimaculata Wiedemann, 1819 .

Generic diagnosis. The genus is diffenent from others by: wide frons, wide parafacial with hairs or setae; orbital setae present in both sexes; ocellar setae very strong and reclinate; outer vertical setae strong; arista thickened on basal half to apex; basicosta reddish yellow; vein R 4+5 with setulae on basal third up to crossvein R-M; section of M between crossveins r-m and dM-Cu distinctly longer than section between dM-Cu and bend of M.

Description (based on Chinese Gonia ). Head yellowish except on occiput and eyes; frontal vitta not darker in ground colour; largely covered with ivory white to golden pruinosity especially on frons and parafacilia; ocellar triangle dark brown; lunule bare. Flagellomere 1 reddish yellow to dark brown; arista dark brown. Palpi reddish yellow; prementum and labella dark brown. Frons and facial regions exceptionally wide; frontal orbital plate much wider than frontal vitta area, frons with one or two additional rows of reclinate or medioclinate setae lateral to frontal row; parafacial with hairs or setae; ocellar setae very strong and reclinate, divergent; orbital setae present in both sexes; outer vertical setae strong; face flat; vibrissa and genal dilation well developed; occiput densely with relatively long, yellow brown setulae. Eye bare. Antennae conspicuously longer in males than in females, male 1st flagellomere 1.5 to 2 times as long as that of female; 1st flagellomere at least 3 times as long as wide, arista bare, thickened on basal half to apex, usually a strong bend at junction of second and third aristal segments giving arista a geniculate appearance, second aristomere 1 to 12 times as long as wide; facial ridges with only a few setae at bases. Prementum 3 to 12 times as long as wide.

Thorax dark brown in ground color with reddish brown pruinosity; dorsum with black or yellow setae or hairs; scutum with four narrow dark brown longitudinal vittae; median vittae straight; short triangular lateral vittae; median vittae short, connected with median presutural vittae; lateral postsutural vittae about twice as long as median vittae with anterior and posterior tips sharply pointed; 3+3 acrostichal setae, 3+4 dorsocentral setae, 1+3 intra-alar setae, two posthumeral, one presutural, three supra-alar, two strong postalar setae; postpronotal lobe reddish brown with three strong setae; notopleuron with two strong and one weak setae; postalar callus reddish brown; proepisternum with single seta; proepimeron with single seta; 3 or 4 katepimeronal setae; anepimeron with one long and one short setae; katepimeron, katatergite, anatergite bare. Wing hyaline with veins yellow brown; tegula and basicosta yellow brown. vein R 4+5 with setulae on basal third up to crossvein R-M, but if with less setulae, then either tegula yellow or wing with an apical dark spot; section of M between crossveins r-m and dM-Cu distinctly longer than section between dM-Cu and bend of M; cell r 4+5 open far away wing top. Lower squamae bare above. Legs predominantly black or reddish yellow; with black or reddish yellow setae and setulae; fore tibia with regular rows of anterodorsal, posterodorsal setulae, medially with two posterior setae; mid femur with posterior apically with 3 to 4 setae; mid tibia with regular rows of anterodorsal, posterodorsal setulae, with two posterior and two ventral setae; hind tibia with regular rows of anterodorsal, posterodorsal setae and 2 to 5 ventral setae.

Abdomen yellow brown to black with white to reddish yellow pruinosity except for syntergite 1+2. Mid excavation of syntergite 1+2 extending to or not to posterior margin. Male terminalia reddish yellow to dark brown; sternite 5 posteriorly with deep median cleft at least 0.6 sternite length; epandrium dorsally and cercus basally with long setae; surstylus very short; and intermedium very small; apical part of pregonite with several setulae; hypandrial arms fused like a bridge; epiphallus apically pointed; ventral surface of distiphallus covered with fine spinules. Female terminalia yellow brown to dark brown, with yellow brown to black setulae; cercus rectangular shape, posterior apically round in lateral view; subanal plate triangular in ventral view (revised after Lee & Han, 2010).

Remarks. Tschorsnig (1985) divided the Goniini into four groups based on their male terminalia structures, according to this classification, Gonia belongs to the Gonia group along with Onychogonia , Pseudogonia , and Spallanzania sharing the following characters: hypandrial arms characteristically fused like a bridge; surstylus very short; and intermedium very small. But Gonia can be separated from Spallanzania by the vein R 4+5 with setulae on basal third up to crossvein R-M, reddish yellow tegula and from Pseudogonia and Onychogonia by the most species with reddish yellow tegula and basicosta.

Distribution. Widely in the World (O’Hara, 2016).