250 MOSQIHTOBS OF NOKTH AMERICA 



joint slightly enlarged; tori subspherical, with a cup-shaped apical excavation, 

 yellowish, brown on inner side. Clypeus rounded triangular, brown, nude. 

 Occiput dark brown, clothed with narrow curved scales on vertex, broader ones 

 on sides, pale brownish, shining, those at sides and along margin of eyes white ; 

 many erect, forked black scales on nape ; setae along margins of eyes rather long, 

 curved, black. Eyes black. 



Prothoracic lobes elliptical, remote dorsally, brown, clothed with shining 

 white scales and dark bristles. Mesonotum dark brown, with two narrow im- 

 pressed lines, vestiture of bronzy-brown and brassy scales, the latter being ar- 

 ranged along the margins and anteriorly along the median line; two oblique 

 subdorsal lines, a patch over root of wing and an area around ante-scutellar 

 space of similar scales, the pattern rather indistinct. Scutellum trilobate, pale 

 brown, clothed with pale-brassy scales, each lobe with a group of brown bristles. 

 Postnotum elliptical, prominent, brown, slightly pruinose. Pleurae brownish 

 with darker mottlings, with patches of white scales and rows of brown bristles ; 

 coxae pale greenish, the anterior pair with brown scales. 



Abdomen subcylindrical, depressed, truncate posteriorly; dorsal vestiture of 

 dull black scales, the segments with very narrow, almost obsolete basal white 

 bands joining large lateral, basal, triangular white patches; tips of segments 

 with pale hairs ; venter white-scaled, with black apical segmental bands. 



Wings moderate, hyaline ; petiole of second marginal cell less than one-third 

 as long as its cell, that of second posterior cell slightly shorter than its cell; 

 basal cross-vein about its own length distant from anterior cross- vein ; scales of 

 veins brownish, those on costa darker and with a bronzy luster, the outstanding 

 ones long and linear, rather dense, particularly towards the tip. Halteres pale, 

 with brownish knobs. 



Legs moderate; vestiture blackish, femora whitish beneath nearly to tip, 

 knees white; tibiae black, bases and apices white, a white line on inner side; tarsi 

 blackish, with a bronzy luster, hind tarsi with broad basal and apical white bands 

 on first four segments, last joint entirely white ; fore tarsi with white spots at 

 both ends of first two and base of third joint, mid tarsi with bands instead of 

 spots. Claw formula, 0.0-0.0-0.0. 



Length : Body about 4 nun. ; wing 4 mm. 



Male. — Proboscis straight, longer than in the female, slightly thickened to- 

 wards apex, black scaled, a white ring at middle, labells pale. Palpi exceeding 

 the proboscis by the length of last joint, slender, penultimate joint slightly 

 thickened, last one tapering at tip ; apical third of long joint and last two joints 

 with numerous long black hairs ; vestiture of black scales, long joint with a nar- 

 row white ring before the middle, last two joints with basal white rings. Antennae 

 plumose; last two joints long and slender, rugose, pilose, black, the others 

 short, whitish, narrowly ringed with black at insertion of hair-whorls ; hairs of 

 whorls long, dense, black. Coloration similar to the female, the brassy scales of 

 mesonotum more abundant; basal abdominal bands broad, laterally expanded on 

 seventh and eighth segments. Wings narrower than in the female, the stems of 

 the fork-cells longer, vestiture sparse. Abdomen densely hairy at sides. Claw 

 formula, 1.1-1.1-0.0. 



Length : Body about 4 mm. ; wing 3 mm. 



Genitalia (plate 14, fig. 97) : Side-pieces over twice as long as wide, the tips 

 conically tapered ; a small truncate prominence before the tip bearing three rods, 

 a leaf -like appendage, and a seta. Clasp-filament moderate, rather stout, tapered 

 at tip, bearing a small articulated terminal spine. Harpes and harpagones 

 divided, lamellar, the harpes with a crest of dense spines on the arm. Basal 

 appendages small, remote, setose. 



