Hybos medialis, Huo, Shan, Grootaert, Patrick & Yang, Ding, 2010

Huo, Shan, Grootaert, Patrick & Yang, Ding, 2010, Two new yellow-legged species of the genus Hybos from Vietnam (Diptera: Empidoidea: Hybotinae), Zootaxa 2512, pp. 47-55 : 48-49

2. Hybos medialis sp. nov.

( Figs. 1–3 , 7–10 )

Diagnosis. Arista bare. Legs brownish yellow except coxae and trochanters black, median portion of hind femur and tarsomeres 3–5 of all legs blackish. Wing dark brown at apex of basal cells and anal cell. Hind tibia with 2 long dorsal setae on apical half in male. Hypandrium apically narrowly incised and with very long setae on apical half.

Description. Male. Body length 4.4–5.2 mm, wing length 4.4–5.1 mm.

Head black, pale gray pollinose. Eyes contiguous on frons, dark yellow, and with enlarged upper facets. Setae and setulae on head black; ocellar tubercle weak, with one pair of long oc and 2 very short posterior setulae. Antenna black; scape bare; pedicel with circle of subapical setulae; first flagellomere without dorsal setulae; arista black, bare with apical 1/4 thin. Proboscis blackish; palpus blackish with 3 nearly dorsal setulae.

Thorax black, subshining, pale grey pollinose except pleuron (excluding laterotergite). Setae and setulae black; h absent, 2 npl (anterior npl short weak, posterior npl long strong), acr in about 6 more or less regular rows, 1 long strong posterior dc and 5 setulae anteriad, 1 short weak presc, 1 long psa; scutellum with 6 short marginal setulae and 2 long subapical setae. Legs brownish yellow except coxae and trochanters black, median portion of hind femur and entire tarsomeres 3–5 blackish. Setulae on legs blackish, setae black, except coxae and trochanters with pale setulae and setae. Fore femur 1.1 X and hind femur 2.1 X as wide as mid femur. Fore tibia with one row of setula-like pv nearly as long as femur thickness; mid femur with row of pv setulae shorter than femur thickness. Hind femur ( Fig. 2 ) with 3 preapical anterior setae, and with nearly four rows of ventrals (7 av mostly slightly longer than femur thickness). Fore tibia with 1 long ad seta near middle, apically with 1 long ad and 1 long pv seta. Mid tibia with 1 very long ad, 1 short ad and 1 very long av seta at middle, apically with 6 setae (1 av very long). Hind tibia with 1 long ad and 1 long pd seta on apical half, apically with 1 av and 1 pd seta. Fore tarsomere 1 with 1 ventral seta at base; mid tarsomere 1 with 1 ventral seta at base and middle; hind tarsomeres 1–2 with short ventral spine-like setae. Wing ( Fig. 1 ) slightly tinged grayish, but dark brown at apex of basal cells and anal cell; stigma dark brown; veins dark brown, R4+5 and M1 slightly divergent apically. Squama dark yellow, bordered with pale setulae. Halter yellow.

Abdomen black, grey pollinose. Setulae and setae on abdomen brownish yellow. Male genitalia ( Figs. 7– 10 ): left epandrial lobe rather wide with weakly concave inner margin, left surstylus finger-like and strongly curved inward; right epandrial lobe wide, slightly longer than left epandrial lobe, with slightly concave inner margin, right surstylus basally rather wide and with long finger-like lateral process; hypandrium much longer than wide, basally narrow, apically narrowly incised obliquely, and with very long setae on apical half.

Female. Body length 3.4–5.2 mm, wing length 3.3–6.2 mm. Similar to male, but differs in following points: Abdomen nearly straight. Hind femur ( Fig. 3 ) narrower, 1.6–1.7 X as wide as mid femur. Hind femur with 2 preapical anterior setae, and with nearly three rows of sparse ventrals (7 av mostly distinctly longer than femur thickness). Fore tibia with 1 long ad seta near middle, apically with 1 long ad and 1 short pv seta. Mid tibia with 1 very long ad near base and 1 very long av seta at middle, apically with 5 setae (1 av very long). Hind tibia with 1 long ad seta at apical half, apically with 1 av and 1 pd seta.

Type material. Holotype male, VIETNAM: Lam Dong, Bidoup Nuiba nr. Dalat, 1650–1700 m, Malaise trap 1–12, Rain forest & Pinus , 12–15.X.2005, leg. C. van Achterberg & R. de Vries. Paratypes: 3 males, 2 females, same data as holotype.

Distribution. Vietnam (Lam Dong).

Etymology. The specific name refers to the black median part of the hind femur.

Remarks. This species is somewhat similar to Hybos bicoloripes Saigusa, 1963 , but it may be separated from the latter by the coxae and trochanters black, wing dark brown at apex of the basal cells and anal cell, and the left surstylus strongly curved inward. In H. bicoloripes , the coxae and trochanters are yellow, the wing is not dark brown at apex of the basal cells and anal cell, and the left surstylus is nearly straight ( Yang & Yang 2004).

Figures

FIGURES 1 – 3. Hybos medialis sp. nov. 1. Male wing. 2. Male hind leg, anterior view. 3. Female hind leg, anterior view. Scale bar = 0.6 mm.

FIGURES 7 – 10. Hybos medialis sp. nov., male. 7. Genitalia. 8. Right surstylus. 9. Left surstylus. 10. Hypandrium. Abbreviations: C = cercus, LEL = left epandrial lobe, LS = left surstylus, REL = right epandrial lobe, RS = right surstylus. Scale bar = 0.5 mm.