60 NEW ZEALAND ENTOMOLOGY. 



maggot eats its way out and changes into a dark-brown 

 pupa. In this condition the parasite is protected by the 

 web which was previously constructed by the unfortunate 

 caterpillar for its own use. The perfect fly appears in 

 about six weeks' time, its great agility and large white 

 scales rendering it very conspicuous. 



Family MUSCID^:. 

 Eurigaster marginatus (Plate VII., fig. 7). 



Another parasitic species, its larva inhabiting the cater- 

 pillars of various noctuae which it destroys just before 

 they change into the chrysalis state. The pupa of the 

 parasite lies in a small oval cell constructed in the earth 

 by its larva. A variable number of these maggots are 

 found associated in one host, the smaller caterpillars only 

 harbouring a single individual, while a large larva will 

 frequently contain three or four. This species has been 

 bred from the following Lepidoptera : Mamestra com- 

 posita, M. iististriga and M. mutans. It also occurs in 

 the curious Qiceticus ommvorus,btmg found in the cocoons 

 of that moth in numbers varying from two to eleven, 

 or even more, and it is especially interesting, as it is in 

 turn destroyed by a small species of Pteromalus already 

 noticed among the Hymenoptera (page 37). The perfect 

 insect occurs occasionally on flowers throughout the 

 summer. 



Family Muscid.e. 



Calliphora quadrimaculata (Plate VII., fig. 9). 



This is the large blue-bottle fly of New Zealand and is 

 found everywhere in great abundance. Its larva feeds on 

 decaying flesh and is of a dirty yellow colour, measuring, 

 when full-grown, about seven lines in length. The pupa 

 is buried at a considerable depth in the ground, the 



