866 MOSQinTOEs or north America 



Prothoraeie lobes elliptical, large, closely approximate dorsally, clothed with 

 broad, metallic dark blue scales and with coarse, stiff, black marginal bristles. 

 Mesonotum black, clothed with elliptical flat scales with bright metallic green, 

 bronzy and blue reflections. Scutellum weakly trilobate, the middle lobe broad; 

 blackish-brown, clothed with broad, flat, metallic blue scales, each lobe with a 

 group of dark bristles. Postnotum elliptical, prominent, brownish-black, 

 usually with one or two minute setae close to posterior margin. Pleura and 

 coxae blackish, nearly solidly clothed with silvery-white flat scales ; setse minute, 

 dark. 



Abdomen subcylindrical, tapered posteriorly, sixth and seventh segments 

 slightly expanded apically beneath; dorsal vestiture of metallic, shining blue 

 and purple scales, a series of large, lateral, segmentary, basal, triangular silvery- 

 white spots; first segment clothed with metallic blue scales in the middle, 

 silvery ones at the sides, and with short, fine pale hairs at the sides ; venter black 

 scaled with metallic violaceous reflection and broad, basal, segmentary silvery 

 bands. 



Wings moderate, hyaline; petiole of second marginal cell shorter than its 

 cell, that of second posterior cell slightly longer than its cell ; basal cross-vein 

 distant about its own length from anterior cross-vein; scales brownish black 

 with violet reflection, the outstanding ones narrowly ligulate. Halteres black, 

 knobs metallic whitish scaled at tip. 



Legs long and rather slender; vestiture dark metallic violet-blue; trochanters 

 silvery- whitish ; mid femora with a narrow silvery line beneath nearly to apex ; 

 hind femora broadly silvered on outer side to apical third. Claw formula, 

 0.0-0.0-0.0. 



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



Male. — Proboscis slender, rather long, gently curved, black-scaled. Palpi 

 short, about one-sixth the length of the proboscis. AntennsE plumose, the last 

 two joints long and slender, rugose, pilose, black, the others short, pale, broadly 

 ringed with black at insertions of hair-whorls ; hairs of whorls long, fine, but 

 rather sparse. Coloration similar to the female. Wings narrower tiian in the 

 female ; stems of the fork-cells longer, that of the second marginal cell being as 

 long as its cell, that of the second posterior longer; vestiture sparser. Abdomen 

 elongate, slender, somewhat expanded towards apex, particularly the seventh 

 and eighth segments beneath, these latter with many coarse black bristles; 

 seventh segment, and sometimes the eighth, dorsally with a small silvery spot 

 medianly at base. Claw formula, 1.0-1.0-0.0. 



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



Genitalia (plate 33, fig. 164) : Side-pieces over twice as long as wide, 

 rounded at tips, a slight rounded seta-bearing prominence from which the clasp- 

 filament arises; clasp-filament long, slender, curved, with a short articulated 

 subterminal claw ; side-piece with large outstanding scales along inner margin. 

 Harpes narrowly elliptical, inner margin revolute, tip thickened and bent, with 

 fine teeth. Harpagones with a long columnar stem, sinuate, capitate, bearing a 

 small inserted lanceolate filament. Unci forming a large basal cone. 



Larva, Stage IV (see figure of the entire larva, plate 77). — ^Head rounded, 

 about as wide as long, rather evenly arcuate all around, a notch at insertion of 

 antennae. Antennae moderate, slender, smooth, a single hair near the middle ; 

 at tip three hairs of different lengths and a digit on a pedestal. Eyes large, 

 transverse. Upper pair of dorsal head-hairs single, long, lower pair double, 

 short; ante-antennal tufts quadruple. Mental plate elongate triangular with 

 stout central tooth and eight on each side, the first five short, rounded and 

 closely set, the sixth sharp and longer than the preceding ones, the last two 

 remote and basally placed. Mandible quadrangular, smooth without; two fila- 

 ments from a notch before tip ; an outer row of cilia from a collar ; a row of 

 long filaments on outer margin ; dentition of four teeth on a slender process, the 



