Megalothoraca flava Enderlein, 1912

Wendt, Lisiane Dilli & Marinoni, Luciane, 2019, Taxonomic revision of Megalothoraca (Diptera: Richardiidae) with description of a new species, synonyms and new combination, Zoologia (e 31456) 36, pp. 1-15 : 4-5

Megalothoraca flava Enderlein, 1912

Figs 5–11

Megalothoraca flava Enderlein,1912: 104 . Holotype male (MZPW). Type locality: Santa Inez, Ecuador. Hennig 1938a: 121 (citation); Steyskal 1968: 5 (catalogue).

Diagnosis and comments. Megalothoraca flava , known only from a male, is distinct by having thorax and legs entirely yellow ( Fig. 5) (other species are brownish, brown or black), spurious vein in R 2+3 absent, and apical brown spot not completely homogenous, with faint hyaline areas on cells r 2+3 and r 4+5.

Redescription. Holotype male, MZPW: Measurements (in mm): body length 12.4 (11.75 according to Enderlein 1912: 105); wing length 13.8 (13.5 according to Enderlein 1912: 105). Head ( Figs 9–11). Head width-to-height ratio 1.36. Frons-to-head ratio 0.33. Frons width-to-height ratio 0.72. Ocelli-distance ratio 2.14; anterior ocellus inserted at dorsal third of frons ( Figs 10, 11). Brown, except prementum, palpus, and posterior half of postcranium yellow ( Fig. 9). Vertex, in frontal view, straight. Frons sparsely whitish pollinose. Parafacial, gena and ventral two-thirds of postcranium, especially at contour eye and extending to occipital foramen, densely whitish pollinose. Vertex and dorsal third of postcranium bright. Postcranium sparsely brown setulose. Orbital and outer vertical areas, extended to vertex, slightly tumescent and bright ( Fig. 11). Ocellar seta present, longer than orbital seta, and inserted at same level. Thorax ( Figs 5, 9). Entirely yellow. Scutum 1.54 times longer than wide. Postpronotal seta absent. Legs ( Figs 5, 7–9). Entirely yellow. Fore ( Figs 7, 8) and mid coxae with strong anterior spine-like seta. Fore femur thicker than mid and hind femora. Left fore femur with five anteroventral and three posteroventral spine-like setae, and right fore femur with six anteroventral and three posteroventral spine-like setae; setae different in size, occupying apical two-thirds of anteroventral surface and apical third of posteroventral surface of femur. Mid and hind femora with one preapical anteroventral spine-like seta, thinner than those on fore femur. Hind coxa setulose on posterior surface. Wing. Generally hyaline except for the following marks: conspicuous brown basal band from vein R 1, from base of bifurcation between R 2+3 and R 4+5 to vein bm-cu, distinctly wider in cell r 1; wide medial brown band, from costal vein to vein M, wider at distal margin in cell r 1, but not reach apical spot, and more diffuse in cell dm, with proximal and distal margins irregular; apical brown spot, as wide as medial band, with diffuses hyalines areas in cells r 2+3 and r 4+5, very faint in cell m, with proximal margin irregular. Vein R 2+3 from apical third equally twice conspicuous and shortly sinuous. Spurious vein absent. Vein M, distal to vein r-m, sinuous and curved towards R 4+5. Vein r-m at distal fifth of cell dm. Halter pale brown. Abdomen. Brown with metallic reflexes, except basal half of syntergite 1+2 and tergite 5 reddish brown. Tergites sparsely and shortly brownish setulose, non pollinose. Syntergite 1+2 with one pair of robust and one pair of weak preapical laterodorsal setae. Sternites brown. Male terminalia. Not dissected. Epandrium and cerci brownish yellow.

Female. Unknown.

Type-material examined. Holotype male, MZPW: “ Santa Inéz \(Ecuad. [ Ecuador])\ R.Haensch S.”; “ Type ” [red label]; “ Megalothoraca \flava\Type Enderl. ♂ [handwritten]\ Dr. Enderlein det. 1912” ( Fig. 6). The holotype is pinned and relatively well preserved, with no part missing; scutum, scutellum, and median region of costal vein of left wing damaged ( Fig. 5).

Distribution. Ecuador.