ART. 10 THE FAMILY SIMULIIDAE DYAR AND SHANNON 3 



about four times as long as broad; mesonotal pile short and fine, 

 longer and coarser posteriorly; scutellum with long coarse pile, 

 directed anteriorly; tarsi slender; hind basitarsus without projec- 

 tion; following joint without basal scale; costa, subcosta and radial 

 veins with rather long hairs on dorsal and ventral surfaces; sub- 

 costal joining costa near basal third of costal vein; radius joining 

 costal vein at its middle; radial sector forked; R4+-, joining costal 

 a considerable distance before tip of costa ; section of radius between 

 stem vein and base of radial sector not longer than section of costa 

 beyond R4+5; fold between media and cubitus scarcely visible and 

 apparently unforked; mesosternum flat, the semicircular portion 

 barely discernible; abdominal tergites and sternites well developed, 

 fully chitinized. Only one species, the genotj^pe. 



PARASIMULIUM FURCATUM Malioch 



Parasimulium furcatum Malloch, U. S. Dept. Agr., Bur. Eut. Tech. Ser., 

 No. 26, 1914, p. 24. 



Antennae pale yellow, basal joint brownish; mesonotum dark 

 brown; pleurae j^ellowish; legs yellowish, hind femora darker; 

 abdomen dark brown ; claws untoothed. 



Only a single specimen is known for this genus and species, which 

 in several respects appears to be the most generalized form loiown 

 for the family. 



Type locality. — Humboldt Co., Calif. Type in U. S. National 

 Museum, Cat. No. 15403, U.S.N.M. 



DistHhution. — California : Humboldt County, June 9, 1903 (H. S. 

 Barber). 



Genus PROSIMULIUM Roubaiid 



PrositnuJiurn Roubaud, Compt. Rend. Acad. Sci. Pari.s, vol. 143, 1906, p. 519. 

 Prosimulium Mai.locii (part), U. S. Dept. Agr., Bur. Ent., Tech. Ser., No. 



26, 1914, p. 15. 

 Prositmtliuin Endeulein (part), Deut.sch. Tierarzt. Woch., Hanover, 1920: 



Zool. Anz., vol. 53. 1921, p. 43. 

 Helodon Ennderlein, Deutsch. Tierarzt. Woch., Hanover, 1920 ; Zool. Auz., 



vol. 53, 1921, p. 43. 



Genotype. — Simuliutii hirtipes Fries. 



Medium sized to large species, usually dark colored, sometimes 

 yellow; antenna usually 11-jointed, sometimes 9-jointed; front usu- 

 ally rather broad, rarely narrow ; clypeus broad, a littlfe longer than 

 its breadth; tarsi slender; hind basitarsus without apical projection; 

 second joint without subbasal dorsal excision, elongate, being much 

 broader than width of basitarsus ; claws bifid or simple ; subcostal 

 joining radius at or a little beyond middle of costal vein; radius 

 joining costa far beyond middle; R^+j joining costal vein very near 

 its tip; radial sector forked (that is, II2+35 distinct from II4+5) ; 



