258 THE HOUSE FLY—DISEASE CARRIER 
ticular species are not known, but its relatives feed in 
the earlier stages on decaying vegetable matter, dead 
insects, snails, etc. The species in question possibly 
fed upon decaying vegetation in the neighborhood of 
the houses in which it was collected. 
The Window Flies (Scenopinus fenestralis L.) 
Comstock has applied the term window dies to the 
little flies of the family Scenopinidie. The term, how¬ 
ever, does not apply to all of them; but the best-known 
Fig- 35 -—Scenopinus fenestralis; a, adult; b, pupa; c, larva; 
d, eggs ; enlarged. (Original.) 
species, namely, Scenopinus fenestralis, is not uncom¬ 
monly found upon windows both in this country and 
in Europe. These flies are usually black and rather 
smooth, A. fenestralis being about one quarter of an 
