The Two-winged Flies 
349 
At cider-making and fruit-gathering time, and in vine-growing districts 
at wine-making time, hosts of tiny yellowish-bodied flies, the pomace-flies or 
fermenting fruit-flies, Drosophilidae, may be seen busily lapping up their 
favorite food, the juices of fermenting fruits. 
The most abundant and wide-spread species 
is Drosophila ampelophila , the vine-loving 
pomace-fly. It is a small, clear-winged, 
red-eyed, brownish-yellow, chubby fly 
which lays its eggs on gathered fruits, 
and especially decaying fruit and pomace, 
and also on grapes still hanging on the 
vines if they have been broken somewhat 
by birds. The larvae or maggots hatch in 
from three to five days, live in the fruit four days, and lie in the pupal 
stage three to five days, so that a whole life-cycle is gone through in less 
Fig. 497.— Trypetalongipennis. (Two 
and one-half times natural size.) 
Fig. 498 —Larva of cherry-fruit fly, Rhagoletis cingulata , dorsal and 
(After Slingerland; natural size and much enlarged.) 
lateral views. 
