PARASITIC DIPTERA. 385 



Several Coleopterous larvae have been found feeding upon 

 the egg-clusters of the gypsy moth, but we have been unable 

 to obtain the imagoes from them. During the past year 

 Mr. C. H. Howe succeeded in rearing a specimen of Ptinus 

 bninneus from a gypsy moth egg-cluster. 



The following species of predaceous beetles are said to 

 attack the gypsy moth in Europe : 



Calosoma sycophanta (L.) (larva). 

 Tiresias serra (Fab.) (eggs). 

 Dermestes ater (Panz.) (eggs and pupae). 

 Dermestes lardarius (L.) (eggs and pupse). 



Diptera. 



In June, 1891, while on a visit to the territory infested 

 by the gypsy moth, my attention was first called to the fact 

 that flies were depositing their eggs on the caterpillars ; and 

 .since that time the field workers have reported these para- 

 sitic flies in no less than ten towns, showing that they 

 probably occur throughout the entire infested region. The 

 number of these eggs on a single caterpillar was reported 

 by twelve different inspectors who observed them, as vary- 

 ing from one to twenty, though some state that they have 

 seen the caterpillars " nearly covered," and others " eggs in 

 great numbers on them." Directions were then given to 

 collect and rear the parasitized caterpillars till these para- 

 sites should emerge. It was found that many of the cater- 

 pillars molted their skins before the eggs of the parasites 

 hatched, and therefore comparatively few of them were able 

 to make their way into their insect hosts and destroy them. 

 If the caterpillars had not molted before the eggs of the 

 parasites hatched, their destruction would have been vastly 

 greater. During the summer of 1893, Mr. Reid collected a 

 number of caterpillars on which the eggs of the parasites 

 had been laid. Two hundred and thirty-five of these cater- 

 pillars, having from one to thirty-three eggs on them, were 

 fed in cages until they changed to pupse; and from these 

 two hundred and twenty-six moths emerged, but only four 

 Dipterous parasites were secured from this entire number. 

 The caterpillar which had thirty-three parasite eggs on it 



