Scione flavescens (Enderlein, 1930)

(Figs 32A–G, 33A–F)

Rhinotriclista flavescens Enderlein, 1930: 65; Kröber, 1930: 163, fig. 9 (rev.); Fairchild, 1966: 12, fig. 19 (Enderlein spp.).

Scione flavescens; Kröber, 1934: 233 (cat.); Fairchild, 1971: 26 (cat.); Moucha, 1976: 40 (cat.); Wilkerson, 1979: 166, figs. 26E–H, 37 (Colombia spp.); Fairchild & León, 1986: 105 (Ecuador spp.) (as S. fluvescens, error); Fairchild & Burger, 1994: 50 (cat.); Buestán et al., 2007: 31 (tax.); Coscarón & Papavero, 2009: 52 (cat.).

Type locality. Ecuador.

Diagnosis. Body yellowish-brown. Clypeus markedly developed. Thorax with conspicuous white longitudinal stripes. Wing smoky with brown spots in the middle of cells r 1, r 2+3 and r 5 and spots brown on crossveins.

Redescription. Female. Body length: 10.6–11.7 mm (X = 11.2 mm, N = 3), wing length: 11.5–11.8 mm (X = 11.7 mm, N = 4).

Head. Frons slightly divergent below, divergence index 0.7–0.8 (X = 0.8, N = 4), frontal index 1.7–1.9 (X = 1.8, N = 4). Frons with a brown quadrangular patch, almost touching the eyes. Vertex dark brown with dense long black setulae, prominent ocellar triangle, orange-brown ocelli. Frons brown covered with yellowish and whitish pruinosity and dense long black setulae. Subcallus brown with slightly dense yellowish pruinosity. Parafacial brown with slightly dense orange pruinosity and sparse black setulae. Gena brown with dense whitish pruinosity and dense long whitish setulae. Clypeus brown with sparse black setulae and slightly dense yellowish pruinosity on the sides, markedly developed, clypeal index 1.0–1.2 (X = 1.1, N = 4). Scape and pedicel yellowish-brown with yellowish pruinosity and long, dense black setulae. Flagellum orange. First segment of the palpus is brown with long dense orange setulae in the proximal portion and short sparsely dense black setulae in the distal portion; second segment orange with short sparse black setulae. Proboscis dark brown, about 4x the height of the frons. Thorax. Scutum and scutellum orange-brown. Scutellum with sparse black and yellowish setulae and white longitudinal stripes. The sublateral stripes quite evident and extend to the posterior margin of the scutum where they connect. The median stripe is less evident than the sublateral stripes. The sublateral and lateral stripes connected by a narrower white stripe at the transverse suture. Notopleuron with tuft of black and yellowish setulae. Anepisternum with tuft of black, yellowish and whitish setulae. Katepisternum and anepimeron with tuft of whitish setulae. Postalar callus with tuft of yellowish-white setulae. Legs yellowish-brown, femora with long, dense black and yellowish setulae, tibiae with short dense black and yellowish setulae. Wing smoky with yellowish spots in cells r 1, r 2+3 and r 5. Brown veins with faint brown spots on crossveins. Abdomen. Tergites yellowish-brown with sparse black and yellowish setulae. Tergites 1 to 6 with tuft of yellowish-white setulae on the central posterior margin. Sternites slightly darkened and sparse black and whitish setulae with small middorsal patches of shiny yellow brown hairs on tergites 1 to 6.

Distribution. Colombia, Ecuador.

Type material examined. Holotype, ♀, deposited at the MNHUB (examined through photographs).

Additional material examined. 1 ♀, “Tambo to Starosa, Cascho Crespejo, Ecuador, VIII-1-35/ Pres. by Mrs. Y. Mexia Collector [photographed specimen]” (CAS); 1 ♀, “ Los Olivos, Carchi, Ecuador, VII-11-1935, 3200 M./ Pres. by Mrs. Y. Mexia Collector” (CAS); 1 ♀, “ Los Olivos, Carchi, Ecuador, VII-11-1935, 3200 M./ Pres. by Mrs. Y. Mexia Collector/ Cornelius B. Philip Collection, Donated to California Academy of Sciences/ Snout to long/ Compared with type ♀ F. albifasciata Macq. C.B. Philip 58, Agrees but type c [abbreviation of Latin cum, with] straw yel [low] bd [body] + [and] chest/ Scione albifasciata ♀ (Macq.) 56, Det. C.B. Philip / Scione albifasciata (Macquart) det. Krolow, T.K., 2012” (CAS); 1 ♀, “ Los Olivos, Carchi, Ecuador, VII-11-1935, 3200 M. [without abdomen]/ Pres. by Mrs. Y. Mexia Collector/ CAS/ Scione albifasciata ♀ (Macq.) 56, Det. C.B. Philip ” (CAS).

Comments. The thorax and abdomen of the holotype are more densely covered with yellowish setulae, which appear to be missing in the specimens examined; these are not in good condition of preservation. On the abdomen of the holotype the tuft of yellowish-white setulae is present on the central posterior margin of tergites 2 to 6 and is much denser than in the specimens seen by us. Scione flavescens is similar to S. albifasciata and S. maculipennis. However, this species has a markedly developed clypeus, unlike the other two species. Furthermore, S. albifasciata has more pronounced patch on the frons and this touches the vertex, unlike S. flavescens which has less evident patch on the frons. Wing of S. maculipennis has smoky brown coloration with yellow spots in the middle of cells r1 and r 2+3 and no lighter areas in the middle of cells m 1 and m 2. Whereas in S. flavescens the yellowish spots are restricted to cells r 1, r 2+3 and r 5. Wilkerson (1979) provides a redescription for S. flavescens that agrees very well with the specimens seen here, however the specimens studied by Wilkerson vary mainly in body length, measuring between 9 and 11 mm.