Ommatius nebulosus, Scarbrough, 2008

Scarbrough, Aubrey G., 2008, New Ommatius Wiedemann from the Americas with two new species groups, keys, and taxonomic notes (Diptera: Asilidae), Insecta Mundi 2008 (32), pp. 1-14 : 4-6

Ommatius nebulosus n. sp.

Fig. 1, 6-14

Description, male. Black. Body 8.6-10.8 mm; wing 6.2-7.4 mm. Head: Face yellow tomentose, vestiture largely yellow setose, 4-6 thin brown bristles in 2 rows; face at antennae 1/6-1/9 as wide as head. Palpus and proboscis yellow or white setose. Antennae, frons, and ocellar tubercle brown setose; flagellum 2-2.4 times longer than wide. Frons and ocellar tubercle yellowish-brown or brown tomentose. Occiput largely gray tomentose, yellowish-gray dorsally, setae largely white; 3-4 thin brown postocular bristles above each eye, proclinate on apical 1/3-1/2.

Thorax: Largely brown tomentose, margins narrowly dull yellow or yellowish-gray; vestiture brown, setae largely absent, sparse along narrow margins; 4 lateral and 2 dorsocentral bristles. Scutellum dull yellowish-gray tomentose with sparse, short, yellowish setae and 2 blackish marginal bristles, latter

about as long as dorsocentral bristles. Pleura yellowish-gray or gray tomentose, vestiture pale; long thin anepimeral seta present, bristle absent; halter yellow or reddish-yellow.

Wing (Fig. 1): Costal margin straight, dilation

absent; apical 1/3 and narrow posterior margin dense microtrichia, sparse or absent basally. Crossvein r-m just beyond middle of cell d; R 4+5 at or just beyond base of m 1; base of m 1 narrow, sides much wider beyond, with basal 1/3 of cell 1.5-2.5 times wider than cell base.

Legs: Coxae yellowish-gray tomentose with

abundant long, thin pale vestiture. Femora largely yellow, apical 1/3 of fore femora anteriorly and dorsally, and apical 1/3 of hind femora entirely dark brown or black; setae largely yellow, long and thin ventrally; bristles largely brown, 3 each on middle and hind femora anteriorly. Middle femora with several setae anteroventrally, usually yellow, sometimes 3-4 brown medially, bristles absent; preapical, yellow posterodorsal bristle thin. Hind femora usually with 3-4 stout, brown anteroventral bristles apically, 2-3 much longer, thinner, and yellow bristles basally; 1-2 preapical posteroventral bristles present; hind femora swollen, 4-4.5 times longer than wide. Fore and middle tibiae entirely Figure 6-12. Male terminalia of Ommatius nebulosus , n. yellow, apical 1/3 of hind tibiae brown; setae largely sp. 6-8) Lateral, dorsal and ventral views. 9) Left

gonostylus. 10-11) Aedeagus, dorsal and lateral views. yellow, long ventrally, about 1/3 as long as tibiae;

12) Left side of the ventral lamella, ventral view. bristles unusually thin, largely brown, yellow on

Abbreviations: As=aedeagal sheath; Avp=aedeagal fore tibia; hind tibiae with short, asymmetrical ventral process; Vlp=Ventral lamella process (Cc); apex, spur-like bristle. Tarsi largely brown with Ce=cercus; Ep=epandrium; Gc=gonocoxite; Dp= dark brown bristles, 1-2 yellow bristles present on distiphallus; Gs=gonostylus; Hp=Hypandrium. basal tarsomere of fore and middle tarsi.

Abdomen: Sides parallel, only slightly wider apically. Most tergites largely brown tomentose with

dark brown setae dorsally, yellowish-gray with pale setae laterally; tergite 1 and basal 1/3 of 2 gray tomentose; sternites gray or brownish-gray tomentose with pale setae.

Terminalia (Fig. 6-12): Largely brown, yellowish setose. Ventral lamella simple, not visible in lateral

view. Epandrium short and narrow, apex pointed; 1 long brownish bristly seta laterally. Gonostylus flat, apical 1/3 narrow and slightly curved anteriorly, apex forked, basal 2/3 wide with numerous setae. Gonocoxite with narrow band of setae along dorsal margin, gonocoxal process simple, not unusually long or wide. Distiphallus horizontal, sheath in dorsal view narrowed anteriorly, wider posteriorly, with pair of ventral plates; distiphallus tubular, apex open dorsally. Hypandrium triangular with preapical transverse band of setae, largely brown and short, 4-5 contrastingly long, apically curved dorsally.

Female. Body 9.2-12.0 mm; wing 7.3-9.7 mm. Legs: Middle femora with 1-2 brown bristles medially; preapical posterodorsal bristle blackish, much thicker than in male. Hind femora with 6-7 anteroventral bristles, only 1 preapical posteroventral bristle present. Tibiae with ventral setae shorter than in male, about 1/4 as long as tibiae. Middle tibiae with apex brownish-yellow. Tarsi with only dark brown bristles. Sternite 7 with 5-6 long brown bristly setae apically.

Terminalia (Fig. 13-14): Tergite 9 narrow, emarginate anteriorly, mid-length about 1/4 as long as cercus, corners extend only to base of ventral lamella laterally. Sternite 8 produced apically, apical margin W-shaped, with rounded corners and median spur; 6 long, unusually thick, brown bristles present. Genital fork with narrow dorsal arms, each slightly arched, base narrow, 1/2 as wide as apex at junction of arms with base. Spermathecae tube-like, elon-

gate, about 3 times longer than wide; base only

slightly wider than rounded apex, surface with

abundant annuli.

Type material examined. VENEZUELA: T.F.

Amaz. [Territorio Federal Amazonas] / Cerro

de la Neblina / base camp 140 m / 0 o 50’N 66 o 10’W /

10-20.ii.1985, malaise trap in / rain forest ~ P.J.

and P.M. Spangler / R.A. Faitoute / W.E. Steiner

(holotype m, NMNH). Paratypes: same data as

holotype (5 m, NMNH); same data as holotype ex-

cept 10-20.ii.1985 (2 m, 4 f, NMNH); same data as Figure 13-14. Spermatheca and ventral view of female holotype except 26-31.ii.1985; no collectors listed (1 terminalia of Ommatius nebulosus , n. sp. Abbreviations: f, NMNH); same data as holotype except 17.ii.1985; Tg9=Tergite 9; St8=sternite 8 .

second label ‘malaise trap in / rain forest baited /

with methyl silicate ~ P. and P. Spangler / R . A. Faitoute / W.E. Steiner’ (2 f, NMNH); same data as holotype except 16.ii.1985 (1 f, NMNH); same data as holotype except 19.ii.1985 (1 f, NMNH); same data as holotype except 21.ii.1985; ~ ‘ malaise trap in / rain forest baited / with eugenol / P. and P. Spangler / R . A. Faitoute / W.E. Steiner’ (1 m, NMNH); same data as holotype except 23.ii.1985; second label ‘P. and P. Spangler / R . A. Faitoute / W.E. Steiner’ (2 f, NMNH) .

Etymology. Latin nebulosus for cloudy, misty or foggy refers to the type series being captured in a cloud forest.

Distribution. Venezuela. Flight season, February.

Remarks. In addition to the characters in the key, O. nebulosus is distinguished from its congeners by its wing venation and characters of the terminalia (Fig. 1, 6-14).