THE DIPTERA 



327 



are laid on caterpillars and other insects, or, in some cases, on the leaves 

 which these will feed upon, and, on hatching, the maggots bore their 

 way into the host and feed upon its tissues, finally killing it. The adults 

 are common around flowers and also in places where plants are growing 

 rankly, and there are many species. 



Family Anthomyiidae (The Anthomyiids) . This family contains 

 many injurious species, the larvae of some mining in the roots and of others 

 in the stems and leaves of important crop plants. Others breed in 

 decaying vegetable and animal materials and excrement and from their 

 habits it is suspected that they may be disease 

 carriers like the house-fly. 



The Cabbage Maggot (Hylemyia brassicce 

 Bouche). The Cabbage Maggot is a native of 

 Europe but has been present in this country 

 for many years. The adult (Fig. 347) is a small, 

 clear^winged fly about two-tenths of an inch long, 

 not often noticed or at least distinguished from 

 other small flies present in the fields. Winter is 

 passed as the pupa in its puparium underground, 

 and also possibly to some extent as the adult, in 

 protected places. At all events, the adult flies 

 are present in the spring as soon as the cabbage 



h 



FIG. 347. FIG. 348. 



FIG. 347. Adult male and female flies of the Cabbage Maggot (Hylemyia brassicce 

 Bouche). About three times natural size. (After N. Y. Agr. Exp. Sta. Bull. 419.) 



FIG. 348. Young Cabbage Plant showing Maggots on its stem. Natural size. 

 (Modified from Britton, Fourteenth Rept. EnL Conn. Agr. Exp. Sta. 1914.) 



and other cruciferous plants are available. The eggs are now laid on 

 or close to the plants. They hatch in a few days, and the maggots 

 (Fig. 348) attack the stem just below the level of the ground where 

 they feed for about 3 weeks, lacerating the cell walls and feeding on 

 the softer tissues, using for the first process a pair of stout, black 

 hooks attached at the mouth which seemingly are extremely modified 

 mouth parts. When full-grown, the larvae leave the plants, enter the 

 ground and form puparia from their larval skins within which they 

 pupate for a period of from 12 to 18 days in most cases, after which the 

 adults emerge and eggs are laid for a second generation. 



