280 



NEW YOEK STATE MUSEUM 



caudal end. A side view of the markings of the second, third 

 and fourth segments is shown on pl.25, fig.7; a dorsal view is given 

 in fig.ll. On the sixth, seventh and eighth segments the markings 

 are less conspicuous. The microscopic spines, though short, are 

 rather coarser than in allied species. Besides these spines there 

 is usually on each segment a pair of small setae. The caudal 

 appendage consists of the usual genital sacks and six setae, three 

 on each side of the apex. 



Imago. (P1.30, fig.lO.) Greenish black; thorax brown; length 

 2 to 2.5 mm. 



Male. Eyes hairy; head deep brown, face between the bases of 

 the antennae yellowish; proboscis, palpi and antennae pale fus- 

 cous, the basal joint of the last deep brown; antennal hairs 

 brownish. Talpus with the first joint about as long as broad, 

 second and third about twice as long as broad, fourth about 1.5 

 times as long as the second. Dorsum of the thorax and the 

 scutellum dusky greenish yellow, the three stripes of the former 

 and the metathorax deep brown. The pleura and the sternum are 

 somewhat paler in color. Sometimes the scutellum and the space 

 between the dorsal thoracic stripes are pale brown. The dorsal 

 surface of the abdomen is velvet black with a slightly greenish 

 tinge, the first segment wholly and the ventral surface of most 

 of the succeeding segments green, posterior margins of each seg- 

 ment subshining black ; the venter of the apical segments blackish. 

 Genitalia pure white, similar to that of Cricotopus shown 

 on pl.24, fig.lO. Upon both the dorsal and ventral surface of each 

 abdominal segment there are two irregular transverse rows of 

 black setae, most numerous on the seventh and eighth segments. 

 These are best seen in a balsam mount. Legs, including* coxae, 

 sordidly yellow, the knees sometimes widely, and tips of tibiae 

 slightly darkened, moderately hairy; apex' of fore tibiae each 

 with one, middle with two short equal spurs ; the posterior tibiae 

 each with one long curved spur, one short one, and a row of 

 slender apical setae. The empodium. at least of the hind feet, is 

 curved and pectinate. The wings are hyaline, the veins distinct, 

 pale fuscous, crossvein not clouded; costa with black setae; vena- 

 tion as figured. Halteres pale. 



Female. Like the male, differing only in sexual cliaracters; i. e. 

 the more robust abdomen, form of genitalia etc. In both sexes 

 the fore metatarsus is about 0.6 as long as its tibia. The green 

 of the first abdominal segment isnot always distinctly visible. 



Var. a. Like the foregoing, but with the abdomen," usuallv in- 

 cluding the venter dull fuscous or brown. Numerous specimens 

 Ithaca N.Y., Chicago 111. 



