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 egg-s. 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 Drosophilidse, 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 



