PSYCHE 
VOL. XXX. OCTOBER 1923 No. 5 
THE GENUS LASIOPOGON (DIPTERA, ASILIDiE)^ 
By a. L. MEi^ANDER. 
State College, Pullman, Wash. 
The genus Lasiopogon is represented in the western states 
by several common species, some of which are undescribed. As 
characters separating these species are not difficult to discern 
the following table is presented in order to bring to date our 
knowledge of the species of this genus. If male specimens are 
available identification is facilitated, since distinctive characters 
are offered by the genitalia. 
The species of Lasiopogon and Cyrtopogon have the face 
strongly gibbose, thus forming a natural group in the Dasy- 
pogoninse. At first sight they appear to intergrade, but the 
two genera are quite distinct in several characters. The species 
of Lasiopogon are browner in general color, and have the abdomen 
nearly parallel-sided. They possess a vertical row of setse on 
the hypopleurse, lack the short first segment of the arista, and 
have the anal cell closed just within the margin. Cyrtopogon 
presents a more tapering abdomen, usually more pilose, the 
hypopleurse with patch of fine pile, the trichostichal hairs, in 
place of bristles, the basal joint of the arista usually distinct, 
and the anal cell usually narrowly open. The male genitalia are 
different in the two genera; in Lasiopogon the lateral valves are 
most prominent, the lower valves being undeveloped, the dorsal 
side is deeply emarginate and furnished with a distinctive 
fringe; in Cyrtopogaon the lower valves are usually large and 
there is no dorsal fringe of setae. 
The species of Lasiopogon known from North America are 
separable on the characters given in the following key. Most of 
the species appear to be western in their distribution. The 
1 Cuntribution from the Zoology Laboratory of the State College of Washington. 
