48 AMERICAN BLACK FLIES OR BUFFALO GNATS. 



7. Scutum with five very distinct brown stripes on a light gray 



ground vittatum, p. 53. 



Scutum with three less distinct stripes, ground color dark gray -pictij)es, p. 55. 



8. Legs mostly yellow rirgatum, p. 57. 



Legs mostly black hunteri, p. 59. 



Simulium nietallicum Bellardi. 



Female. — Black, shining. Frons glossy, only slightly poUinose; 

 face thickly covered with pollinosity which is slightly pearlaceous 

 in color; antenna? with the basal two joints and most of third joint 

 yellow. Scutum with three stripes, the central one narrow, the lat- 

 eral ones anteriorly dilated and posteriorly divergent, then curved 

 inward and ending at about last third of scutum; viewed from be- 

 hind these stripes are iridescent or pearlaceous in color; from in 

 front they are opaque black, and the remainder of scutum is pearla- 

 ceous; prescutimi brownish; pleura? with pearlaceous dusting, glossy 

 black ; scutellum brownish opaque ; postscutum with pearlaceous dust- 

 ing. Abdomen black, opaque on basal four segments, glossy black on 

 apical four, side of first segment under basal scale with pearlaceous 

 dusting, next three with narrow, lateral, whitish, posterior margins. 

 Legs black, yellow as follows: Coxoe at apices, trochanters, and 

 femora of fore pair ; trochanters, bases of tibiae, most of basal, second, 

 and third joints of tarsi of mid pair; trochanters, bases of tibise, all 

 but apex of first, and basal half of second tarsal joints of hind pair. 

 All tibise silvery white dusted on dorsal surfaces. Halteres bright 

 yellow, stalk brown. Wings clear, basal veins brown, thick veins 

 yellow. 



Frons slightly divergent-sided, less than one-third as wide at up- 

 per angle of eyes as width of head, surface hairs sparse, brown ; face 

 nearly as long as frons and one and one-half times as long as broad, 

 surface hairs pale brown; hairs on palpi brownish; postocular cilia 

 brown. Scutum with sparse, yellow, decumbent, scale-like j)ilosity 

 which is longer posteriorly ; pleural tuft weak, brown ; scutellum with 

 long, upright, brown hairs on hind margin. Abdominal basal fringe 

 rather short, yellowish, surface hairs on abdomen sparse, brown. 

 Legs with brownish-yellow pilosity and scattered, upright, dorsal, 

 brown hairs; fore tarsi dilated, basal joint as broad as tibia, and 

 like the third furnished with the apical paired hairs; claws as shown 

 on Plate II, figure 17. Thick veins of wings with black-brown sur- 

 face hairs and short bristles, thin veins very indistinct. 



Length, 2 mm. 



There are quite a number of specimens in the collection whicli I 

 consider are referable to this species. The localities are: Trinidad, 

 West Indies (F. W. Urich) ; Arroyo di los Nogales, Chihuahua, 

 Mex. (C. H. T. Townsend) ; San Jose, Costa Kica, Cordoba, and 



