470 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



12 bristles on each side. Vertex deeply excavated ; the 

 ocellarium is only moderately high and bears on each 

 side 6 long, slender bristles. 



Thorax : The mesonotum bears a narrowly separated, 

 double irregular row of acrostical elements and has 

 dorsocentral, bristly hairs which are equally fine and 

 short and suberect laterally. Humenis with a dense 

 tuft of long, fine, black pile. All lateral bristles are 

 black and consist of 2 quite long, notopleural, a row of 

 5 supraalar bristles continuing back to the postalar re- 

 gion, 3 postalar, and an irregular row of 6 to 8 prescu- 

 tellar bristles of vaiying tliickness; there are 4 pairs 

 of scutellar bristles. The scutellar margin is impressed, 

 the disc quite convex, brownish yellow pollinose, 

 densely fine, erect, long, black pilose. Metanotal slopes 

 buUose and creased medially and with a dense tuft of 

 rather long, erect, stiff, black pile. There are no bristles 

 on the pleuron, except an irregular, vertical row of 6 

 weak, black bristles and more numerous anterior, long, 

 yellow hairs, fanlike on the metapleuron and 9 weak, 

 long, black bristles on hypopleuron. The upper sterno- 

 pleuron, postmesopleuron and the pteropleuron each 

 bear abundant, rather long, fuie, erect, black pile. Pro- 

 notum with about 8 pairs of slender, black bristles. 

 Lateral metastemum densely long pilose; postmeta- 

 coxal area membranous. 



Legs : The anterior coxa has long, stiff, yellow pile 

 and 2 slender, black bristles; the middle coxa with a 

 tuft of 6 or 8 rather stout, black, anteroventral bristles ; 

 postcoxa with 1 weak, lateral and 1 weak, anterior, 

 black bristle. The hind femur is moderately slender, 

 the other femora rather stout, especially basally ; all of 

 the legs totally black and black pilose, except for a 

 little pale pile behind on the anterior four femora. Tlie 

 mats of setae on the anterior tibia and tarsus are con- 

 spicuously rust brown. The hind femur bears 5 lateral 

 and 6 ventral bristles on the lateral aspect, 4 ventral 

 bristles on the basal third, and 4 also longer, ventro- 

 medial elements on the basal half, besides some equally 

 long, fine, black, bristly hairs and a few, long, basal, 

 reddish yellow hairs. Hind tibia with 3 dorsal bristles, 

 1 of which is quite at the base, 1 ventrolateral on the 

 outer third or just beyond it; the pile is short, subap- 

 pressed and black ; apical black bristles strong ventrally 

 and laterally. The middle femur has conspicuous, ven- 

 tral black bristles in a double row consisting of 6 an- 

 terior and 9 posterior, emphasized basally; 1 lateral 

 and 1 posterior bristle, both at apex. The tibia has 

 strong bristles ventrally, a double row of 3 or 4 in each 

 row which becomes much stronger at the apical fourth. 



The anterior femur has 1 strong bristle in the middle 

 posteriorly, 4 weak bristles anteriorly in a cluster at the 

 apex, and numerous, slender, weak, black bristles ven- 

 trally consisting of 14 to 16 elements in a double, irregu- 

 lar row. Ventrally there is dense, rather short, fine, 

 yellowish white pile, which is erect; it begins in the 

 middle and continues in the middle laterally. The ante- 

 rior tibia has 3 or 4 very long, stout, black bristles j)os- 

 teriorly and toward the base 4 very fine, long, black. 



posterior hairs; apex with 1 rather long, stout, black 

 bristle dorsally, 2 anteriorly, 3 ventrally, and 1 or 2 

 posteriorly. The relatively short basitarsus has 3 ante- 

 rior bristles on the base directed downward instead of 

 outward and 2 anteriorly at apex, others ventrally. 

 Claws not very sharp at apex, curved from the base; 

 pulvilli thm, subtruncate, nearly as long as claw ; em- 

 podium short, half as long as claw and strongly thick- 

 ened at the base. 



Wings: The wings are comparatively slender. The 

 marginal cell is wide and rippled but the wings are not 

 expanded anteriorly. Apex of the marginal cell attenu- 

 ate, the stalk is not long. The 2 branches of the third 

 vein end rather near; the posterior branch ends at or 

 immediately below the apex. The posterior branch and 

 the anterior branch of the fourth vein are both strongly 

 sinuous, causing the long, slender, first posterior cell to 

 be wavy and sinuous. Fourth posterior cell small, 

 closed with a long stalk, all its sides convex. The sec- 

 ond basal cell ends in two veins. Alula large, ambient 

 vein complete. 



Abdomen : The abdomen is cylindrical and not quite 

 as wide as the mesonotum, except on the short, first 

 tergite, which is only about a fourth as long as second 

 tergite, but is rather protuberant laterally, very 

 strongly creased anteriorly, abrupt and slielving behind 

 with dense, wide band of very fine, brownish yellow 

 pile and bears 7 or 8 weak, long, brownish yellow bris- 

 tles. Sides of second and third tergites with moder- 

 ately long, dense, erect, fine, brownish brassy pile, much 

 shorter on the remainder. There are no bristles or spe- 

 cial pile beyond the first tergite. Females witli five 

 normal tergites ; the fifth to the third tergites of nearly 

 equal length. The sixth and seventh tergites are also 

 long but are strongly compressed laterally and attenu- 

 ate, strongly ridged, ci'eased or striate vertically; the 

 eighth segment is drawn out into a long, slender process 

 similar to Astochia Becker. Males with eight tergites. 

 The superior forceps of the male rather prominent, ob- 

 tusely truncate at the apex and thrust strongly and 

 obliquely upward, the proctiger thrust backward. A 

 wide, angular gap is left between the superior forceps 

 and the short, triangular gonopod. Hypandrium pres- 

 ent and moderately long. 



Distribution: Palaearctic: Nyssomyki ochracea, new 

 species. 



Nyssomyia ochracea, new species 



Length 37 mm. Male, female. Head: The face is 

 black, covered with thin, brownish yellow pollen but 

 with a more conspicuous, sublateral, attenuate spot of 

 reddish brown i^ollen on each side beneath the antennae. 

 Upper and lateral mystax of face black, and extends 

 to the bottom of the head and encloses a central triangle 

 of abundant, yellowish white mystax, which extends 

 down to tlie anterior, ventral edge of the facial gib- 

 bosity. Pile of front weak, long and black. Occiput 

 brownish yellow pilose below, black pilose above and 

 with long, doi"sal, black bristles near the vertex. Hairs 

 of ocellarium black. 



