THE CHEESE FLY 
249 
masses of the larvae and pupae of the imported elm 
leaf beetle; also from a decaying squash. Aldrich in 
Idaho has reared it from rotting radishes. In Wash¬ 
ington it has been reared from human excreta. The 
complete round of a generation is said to occupy from 
five to six weeks. (Fig. 25.) 
This fly is one of the dangerous occasional inhab¬ 
itants of houses, not only because it may breed in hu¬ 
man excreta, but because it is greatly attracted to this 
substance when it chances to be deposited in the open. 
There seems to be no especial reason why it should be 
called the stable fly, since the preferred food habits 
of its larvae should make it more abundant away from 
stables, and its scientific name stabulcins was given to 
it by Fallen before its real habits were known. 
It is interesting to note, by the way, that the larva 
of the fly has been found to have passed through the 
human stomach, to which it had probably gained en¬ 
trance through the eating of spoiled vegetables. 
The Cheese Fly (Piophila casei L.) 
The little, shining-black flies of the genus Piophila 
breed in cheese, ham, chipped beef, and other fatty or 
spoiled and decaying animal matter. The eggs hatch 
into small, white, cylindrical maggots which feed upon 
the cheese or meat and rapidly reach full growth, at 
which time they are one-half of an inch in length. The 
maggot is commonly called the cheese skipper or the 
ham skipper from its wonderful leaping powers, which 
it possesses in common with certain other fly larvae, all 
