FIELD BOOK OF INSECTS. 



Adults of the Apple Maggot (Plate LXXI) 

 Rhagoletis are tQ be found frQm j, tQ September> 



pomonella _ . , 



JBy means of her sharp ovipositor the 



female punctures the skin of the apple and lays her eggs 

 directly in the pulp. The white larvae, which taper some- 

 what toward the front, make winding burrows through the 

 pulp and attain a length of .25 in. or more. They then 

 bore out, usually after the apple has fallen, and go about 

 an inch underground where they spend the winter and 

 spring in a brownish puparium. 



The larvas of similar flies, Rhagoletis cingulata and 

 R. fausta, are the cherry-worms, known to us ah 1 . The 

 currant and gooseberry worm is the larva of Epochra 

 canadensis. Several species make galls on goldenrod 

 stems (see p. 457), others mine leaves, live in roots, berries, 

 and fruits of numerous kinds, but practically all have 

 wing-patterns which are distinctive of the species. 



PlOPHILID^E 



Ever see Cheese Skippers? Probably not unless you 

 have lived moderately long or quite near to Nature. The 

 acrobats are larvas of Piophila casei (Plate LXXI). 

 They are about .2 in. long, smooth, and tapered toward 

 the front. The leap is accomplished by holding the tail 

 with the mouth, pulling hard, and then letting go. Why, 

 I do not know. They live also in bacon or other fatty 

 material. 



DROSOPHILID^: 



The little red-eyed Pomace-fly (Plate 



Drosophila LXX) also called Sour Fly and Vinegar- 

 melanogaster 



fly is sometimes common about the fruit 



basket on our sideboard, but it is in the study of heredity 

 and sex that it has become famous, under the name of 

 D. ampelophila. Its larvas feed on ripe, or over-ripe, 

 bananas and other fruit, also on vinegar, stale beer, and 

 the like. The average duration, at living-room tempera- 

 tures, of the egg period is about 2 days; of the larval 

 period, about 6 days; and of the pupal period, about 5 



276 



