AKT. 10 THE FAMILY SIMULIIDAE DYAK AND SHANNON 33 



Externally the species agrees in color and structure with meri- 

 dionale. Cerci rounded quadrate, infuscated, setose. Anal lobe 

 s-imilar, arcuate, moderate, the ventral edge slightly chitinized and 

 irregular. Ovipositor flaps membranous, angular, the tips sepa- 

 rated. Genital rod with the forks at right angles, pale to middle, a 

 long chitinous tooth from the base of a similar rod that runs to tip 

 of arm; a triangular flap at the tip. (Figs. 63a and 64.) 



Male hypopygium : Side-piece longer than broad, outer tip shoul- 

 dered. Clasper uniform tapered, with small terminal spine. Ad- 

 miniculum broad, membranous, shallowy emarginate centrally, sub- 

 pilose. Adminiculum arms with 3 very large teeth on each side, 

 with fimbriae between; lateral plate slight. (Figs. 131 and 132.) 



S. occidentale, also called " cholera gnat " and " turkey gnat," is 

 one of our commonest and widest distributed species. In former 

 years (about 1888) it was believed to have caused the death of thou- 

 sands of chickens and turkeys yearly in Virginia by giving them 

 cholera. It bites man and livestock freely (Townsend). 



Type localities. — Of occidentale, Rio Grande Valley, N. Mex. 

 Present location of type unknown to us. 

 Of ta77iaulipense., Tamaulipas, Mexico. Present 



location of type unknown to us. 

 Of forbesi, Havana, 111. Type presumably in 

 the State Natural History Laboratory. 

 Two hundred and twelve specimens at hand. No material in the 

 collection from Northeastern America, although it is reported from 

 New York (Johannsen). 



DiatHhutioii. — Alaska: Skagway, June 4, 1919 (Harrington). 



California: Tahoe City, June 14, 1920 (H. G 



Dyar). 

 District or Columbia : Washington, May 16, (F 



Knab). 

 Florida: Jacksonville (T. A. Slosson). 

 Georgia: Oxford, March 29, 1915 (Wilson Gee). 

 Myrtle, April 3, 1916 (A. A. Girault). Cornelia, 

 May 3, 1916 (W. W. Chase). 

 Idaho: Idaho Falls, July 18, 1922 (H. G. Dyar). 

 Illinois: Havana (A. W. Jobbins-Pomeroy). 



Urbana, November 13, 1915 ( ). Meredo- 



sia. May 28, 1917 ( ). Galena, June 29. 



1892 (C. A. Hart). 

 Indiana: Pine Creek, May 18, 1917 (J. M. Al- 



drich). 

 Kansas: Lawrence (J. M. Aldrich). 



