PROSIMULIUM. 19 



Frons divergent-sided, occupying less than one-third the width of 

 head at upper angle of eyes, and two-thirds as wide above antennae 

 as at upper angle, surface covered with close-placed, yellow, hair- 

 like pilosity; face slightly narrower than frons at upper angle and 

 distinctly longer than broad, haired as frons; palpi pale-haired, 

 postocular cilia pale. Scutum covered with very closely placed 

 yellow pilosity, which is much longer and upright on posterior fourth, 

 no black hairs present; pleural tuft pale yellow, carried almost to 

 lower margin ; scutellum with decumbent yellow pilosity, and long, 

 upright, yellow hairs. Abdominal basal fringe yellow, all segments 

 covered with moderately closely placed, yellow, hairlike pilosity. 

 Legs with yellow pilosity, and similarly colored upright dorsal 

 hairs; fore tarsi slender, joints without apical paired hairs; claws 

 simple. Fork of radius distinct, group of hairs at base of first thick 

 vein yellow ; beyond this the hairs on surfaces of veins are brown. 



Length, 3.5-4.5 mm. 



Localities of specimens examined : Ithaca, X. Y. (O. A. Johann- 

 sen) ; Wellesley, Mount Tom, and Cohasset, Mass.; Cape Charles, 

 Newfoundland; Morristown and Germantown, Pa.; Kingston, 

 R. L; Rigolet, Labrador; and Moscow, Idaho (collection C. W. 

 Johnson) ; Cabin John, Md. (J. R. Malloch) ; White Mountains, 

 N. H. (Morrison); Mount Katahdin, Me.; Williams, Ariz. (H. S. 

 Barber) ; Kaslo and Laggan, British Columbia (Dyar and Cau- 

 dell) ; Plummers Island, Md. (W. L. McAtee). The dates of cap- 

 ture are for the Eastern States confined to the latter part of April 

 and larger part of May; the specimen from Arizona was taken on 

 June 3. The specimens from British Columbia bear the dates July 

 and August, one from Maine (3,000 feet level) August, and the 

 Newfoundland and Labrador specimens were taken in July. In the 

 collection of the Illinois State Laboratory of Natural History there 

 are two females of this species from Algonquin, 111., one of which 

 bears the date April 29, 1895 (Nason). 



Male. — Similar in color and size to the female, but as a rule there 

 is less tendency to have the base of the antennae and portions of the 

 legs pale. The hairs and pilosity are much darker, being uniformly 

 brown, or yellowish brown, and much longer, especially the basal 

 fringe on abdomen. The hind legs are much more dilated, especially 

 the basal tarsal joint, and the claws are trifid. 



There is no indication of pollinosity on thorax or abdomen in 

 any specimen I have examined. 



Larva. — Yellowish brown in color ; antennae as in Plate VI, figure 

 3, mandibles with the apical teeth black, the smaller ones yellowish; 

 labium with the teeth mostly trifid (PI. Ill, fig. 3). The maxilla of 

 the larva is shown in Plate III, figure G. This is the largest species yet 



