THE 
AMERICAN NATURALIST 


Vor. XXXVI. March, 1902. No. 423. 




A REMARKABLE OCCURRENCE OF THE FLY, 
BIBIO FRATERNUS LOEW. 
JAMES G. NEEDHAM. 
Nor far from my home in Lake Forest there is a forty-acre 
patch of woodland pasture that has been enclosed but not 
grazed for a number of years. It has become well overgrown 
with a thick blue-grass sod. Save for a few young hawthorns 
in scattered clumps, there is no underbrush. The open wood 
consists mainly of white oaks. Black oaks were originally 
abundant but have been cut down, and now the sod is thickly 
dotted with their rotting stumps. Around the bases of these 
stumps, where the sod closely enwraps them, is the larval home 
of Bibio fraternus. 
I had seen but few specimens of this fly until the spring of 
1901, and was wholly unacquainted with its immature stages 
and with its larval habitat. It chanced that on walking across 
this pasture in April I kicked over a rotten stump, and, where 
a lateral root pulled out from under the sod, there in the fine 
black soil that had resulted from the complete decomposition 
of the bark were a large number of dipterous larvae, which 
later, when reared, yielded imagoes of this species. a | 
181 : d 
