44 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 69 



fjenital rod moderate, a long tooth from the base of marginal 

 chitinization that runs to apex. (Figs. 84 and 85.) 



Male hypopygium. Side piece wider than long, setose only at 

 outer rim, clasper twice as long as side piece, with a short rounded 

 spinose arm near base; a spine at tip. Adminiculum transverse 

 quadrate, heavily chitinized on margins and long basal prongs, 

 margin emarginate, denticulate. Adminiculum arms with a row of 

 close teeth mixed with fimbriae; lateral plates moderate. (Figs. 119 

 and 120.) The male hypopygium is very similar to that of the 

 European S. tuherosum Lundstrom, except for the spines on the lobe 

 of side piece. 



Near slossonae^ the arms of the claspers spinose instead of pilose, 

 the adminiculum more chitinized and quadrate. 

 Type locality. — Dead Run, Fairfax County, Va. 

 Type. — Male, paratypes thirteen males and females. Cat. No. 

 28346, U.S.N.M. 



The larvae and pupae live in the swift waters of Dead Run stream 

 just where it begins its descent over a precipitous rocky hillside. 

 Thirty-five specimens. 



Distribution. — Maryland: Forest Glen, May 18, 1914 (O. Heide- 

 mann). Plummers Island, June 5, 1903 (,W. V. 

 Warner), 

 South Carolina : Gramlin, August 20, 1912 (Jen- 

 nings and King). Columbia, May 14, 1912 (Jen- 

 nings and King). Ninety Six, April 19 

 (Jennings and King). 

 Virginia: Dead Run, Fairfax County, April, 1925 

 (R. C. Shannon). 



SIMULIUM VANDALICUM, nev.' species 



Male 'hypopygium: As in perissv/m, but the basal branch of the 

 clasper is reduced to a narrow, heavily spinose ridge. (Figs. Ill and 

 112.) Females from the same locality and collecting are indistin- 

 guishable from venustum. 

 Eleven specimens. 

 Type locality. — Fallen Leaf, Calif. 



Type—Male, paratypes 6 females. Cat. No. 28347, U.S.N.M. 

 Distribution. — California: Fallen Leaf, June 28, 1916 (H. G. 



Dyar) , July 17, 1917 ( ) . Lake Tahoe, June 



13, 1920 (H. G. Dyar). Summit, Placer County, 

 July 19, 1915 (H.'g. Dyar). Lily Lake. June 8, 

 1916 (H. G. Dyar). 



SIMULIUM JACUMBAE. new species 



Male hypopygium: Side piece short, wider than long, oblique, a 

 long basal projection outwardly. Clasper very long, curved, flat- 



