THE FRUIT FLIES 
251 
that the larva over-winters in the puparium. Other 
writers say that the insect passes the winter as an adult 
fly. (Fig. 26.) 
In this country this fly does not play so important 
a part as a cheese insect as it does as an enemy to 
smoked meat. It seems certain that the mother fly 
prefers the older and richer cheeses in which to de¬ 
posit her eggs. Her taste is excellent, and, while it 
is a fair thing to say that skippery cheese is usually 
the best, it will hardly do to support the conclusion 
that it is good because it is skippery, although this con¬ 
clusion is current among a certain class of cheese eaters. 
The cheese fly, under ordinary circumstances, is not 
a dangerous species, but it is well to remember that 
not only has it been reared from dead bodies, but that 
it is also attracted to excreta of all kinds. 
The Fruit Flies (Drosophila ampelophila Loew) 
The minute flies of the family Drosophilidae, com¬ 
monly known as fruit flies or pomace flies, are attracted 
to decaying vegetation, especially to fruit, and are fre¬ 
quently found in houses in the autumn about dishes 
containing pears, peaches, and grapes. They are at¬ 
tracted to fruit both for food and for places to lay 
their eggs, since their larvae live in decaying vegetable 
matter. 
The commonest of the fruit flies in the United States 
is Drosophila ampelophila. It occurs also in the West 
Indies and South Europe. It does considerable dam¬ 
age to canned fruits and pickles, breeds in decaying 
