Occasional Papers of the Museum of Zoology 5 



aration of the species of Dizonias will be found in the struc- 

 ture of the genitalia rather than in the color of the body, which 

 has been used bv previous authors. 



Tozvnsendia- iiiger Back. — The genus Townsendia, erected 

 by Williston for a species from Tabasco, Mexico, is peculiar 

 .among North American Asilidae in having only four posterior 

 cells. So far as I find, five specimens of the genus are men- 

 tioned in entomological literature, and these have been placed 

 as four species. Two specimens in the collection under con- 

 sideration and three specimens in my collection appear to 

 agree best with T. niger, although, as Back states, the differ- 

 ences between ininuta and niger are not pronounced. The five 

 specimens before me extend the range of the genus and indi- 

 cate a rather wide distribution, as they come from Winfield, 

 Louisiana, Decatur County, Georgia, and Dayton, Kentucky. 

 Williston described miniita from two specimens, one from 

 Tabasco and one from New Mexico. Back described pulcher- 

 rima from Travis County, Texas, and niger from South 

 Amboy, New Jersey, each from a single specimen. And Bezzi 

 has described fiehrigvi from one specimen from Paraguay in 

 Annals of the Hungarian National Museum, 1909. 



Proctacanthus mystaceus Macquart. — Several specimens of 

 this South American species from Riohacha, Magdalena, 

 Colombia, were collected by F. M. Gaige. They correspond 

 closely in size and somewhat in appearance to specimens of 

 Proctacanthus brei'ipennis Wiedemann, but are easily known 

 by the elongate second submarginal cell with its base plainly 

 before the base of the second posterior cell or nearly opposite 

 the middle of the length of the section of the fourth vein, 

 which reaches from the anterior cross-vein to the base of the 

 second posterior cell. None of the North American species 



