6 PROCEEDINGS OF THE NATIONAL UNION. VOL, 62. 
it to this genus. Williston figures a species which appears to agree 
exactly with longipennis except that the fourth posterior cell is open 
while it is closed before the margin in Thomson’s species. He men- 
tioned this genus in this connection because it has no empodia and 
has many characters in common with Leptogaster. However, the 
normal development of the anal angle of the wing and especially the 
form of the analcell, which is almost closed in the margin, indicates 
a considerable divergence from the Leptogaster type. 
