THE DIPTERA. 63 



in which a number of these little flies were produced 

 from a pupa of Uloma tcnebrionidcs (Plate II., Figs. 2, 

 2a, 2b), which I was rearing at the time (page 29). In 

 this case it is difficult to understand how the female 

 contrives to deposit her eggs in a horny beetle larva 

 which lies safely hidden in its narrow tunnel in the middle 

 of a large log of wood. Among bees this is a most 

 destructive insect, its larva being parasitic in their grubs, 

 and thus greatly reducing the population of the hive, 

 which is finally ruined by the wholesale destruction of 

 its honey when the flies emerge. Driving the bees into a 

 fresh box would, no doubt, be frequently beneficial in 

 these cases, but it is to be feared that bee-keepers will 

 have much difficulty in contending with this insect. Its 

 sexes are readily distinguished by their size, the female 

 being considerably the larger. 



Family MUSCID^:. 

 Coelopa littoralis (Plate VII., fig. 13). 

 Extremely abundant on the sea-beach. Its larva feeds 

 on decaying seaweed, burying itself in the sand before 

 changing. The perfect insects often congregate in such 

 vast numbers on some of the rocks that it is necessary to 

 run past them in order to avoid being positively suffocated 

 by the countless multitudes which fly up into one's 

 face. This insect must be regarded as the New Zealand 

 representative of the well-known dungfly of England 

 (S. stercoraria), which many of my readers will recollect 

 has a similar habit of assembling in great numbers. 



Family CEstrid/E. 

 GEstrus perplexus, n.s. (Plate VII., fig. 12). 

 This species is mentioned here as it is the only New 

 Zealand exponent of a very important and well-known 



