44 AMERICAN BLACK FLIES OR BUFFALO GNATS. 



white; hairs on palpi brown; postociilar cilia pale, with a consider- 

 able admixture of black hairs. Scutum with a slight indication 

 of a central black stripe in front; pilosity very close and short, 

 yellow, the normal long upright hairs on posterior depression incon- 

 spicuous; plural tuft brown; post-spiracular area pale haired; scu- 

 tellum with yellow pile and long upright black hairs. Abdominal 

 basal fringe pale brownish yellow ; segment beneath scale silv^ered, 

 yellowish except at apex; apical segments with numerous short 

 brown hairs Avhich are longer on lateral margins. Fore tarsi flat- 

 tened, the normal j)aired apical hairs present, surface pilosity pale and 

 short, the upright hairs not very conspicuous; claws simple. Wings 

 with brown hairs at base of first vein. 



Length, 2-2.5 mm. 



Male. — Opaque black. Antenna black, the basal two joints and 

 base of third joint yellowish. Scutum velvety black, posterior and 

 lateral margins with silvery pollinose dusting, disk with an oblique 

 backward and inwardly directed white stripe which stops short of 

 middle, pilosity j^ellowish brown. Abdomen with basal fringe 

 brownish; segments opaque blacj^; first segment, below scale, pear- 

 laceous pollinose ; apical A^entral segments similarly pollinose. Legs 

 black; anterior tibiae with basal half yellow, and whitish pollinose 

 on the dorsal surface, hind and mid tibia? only yellow at bases (Plate 

 V, fig. 1) ; fore coxse, base of basal mid tarsal joints, and bases of 

 basal and second hind tarsal joints yellow; claws trifid. Otherwise 

 as in the female, except in the confluent eyes. 



Larva. — Yellow, with dark cross-bands on the segments. Fans 

 with about 60 rays. Labium with middle tooth longest, the outer 

 one slightly shorter, and the three intervening teeth considerably 

 smaller. 



Piqya. — Eespiratory filaments six in number (PL IV, fig. 3). Co- 

 coon shaped like a small conical pocket and attached to leaves or 

 stems of plants growing in the water. The cocoons are very closely 

 placed and almost identical Avith those of vittatuin and jenningsi. 



This is one of the commonest species in the genus. There has 

 been much confusion regarding the identity of this and closely allied 

 species, and possibly there is more than one species among those I 

 have before me. An exhaustive study of the early stages may settle 

 this question, but the material before me at present does not permit 

 of my forming a definite opinion as to the specific distinctions of some 

 of the specimens. I have described the male and female above from 

 the same lot of reared specimens, the larvae and pupae of which agree 

 with those described by Johannsen. The species was originally de- 

 scribed by Say from Shippingsport, Falls of the Ohio. 



The material in the U. S. National Museum collection is from the 

 following localities: White River, Ontario, and Oxbow, Saskatche- 



