206 THE CANADIAN ENTOMOLOGIST. 



forth over the cluster of cocoons, the males evidently waiting for the 



females and the females waiting to be fertilized. Mating takes place a 



short time after emergence, within 12-24 hours. 



Immediately after fertilization the females go in search of their host 



larv^. Any cabbage leaves placed in the breeding cages soon attracted 



their attention, and, if any unfortunate larvae were present, they soon fell 



victims to these parasites. Walking back and forth over the cabbage 



leaves, the females kept their antennae in constant motion. As soon as one 



found a larva, not too large, preferably in the first, second or third stages, 

 she prepared to oviposit. Bending her abdomen almost at right angles to 

 her body, the parasite rushed upon the Pieris larva and drove her 

 ovipositor through the skin, while her wings, in nearly all cases, were 

 extended dorsally, closed above the thorax. I never observed ihem 

 oviposit on the dorsum, always on the latero-ventral region, and it was not 

 infrequent to observe two or three ovipositing in a single larva at the same 

 time. The host usually objected most vigourously to such treatment, but 

 the parasites remained unmoved, stroking the larva with their antenna^ or 

 remaining motionless. Sometimes they endeavoured to oviposit in an 

 older larva, but it succeeded in knocking them off, though undoubtedly 

 some eggs were deposited. The time of oviposition varied from fifteen to 

 twenty seconds. At each act of oviposition from fifteen to thirty-five eggs 

 are deposited just beneath the epidermis, so that with the moulting of the 

 host the eggs are not shed also. In one larva oviposited in three times I 

 counted, when dissected, sixty-five eggs, and undoubtedly there were a few 

 more which I did not succeed in finding. These eggs were found floating 

 freely in the body cavity, and were not inclosed in packets. These facts 

 stand in striking contrast with Reaumur's and Bree's observations. 



These eggs hatch in from three to four days. Tne larvi« feed upon 

 the lymph and fatty tissue of their host, carefully avoiding the vital parts. 

 They become mature during the latter part of the larval life of their host — 

 that is, in about eight to twelve days — and emerge by cutting their way 

 through the skin. The spinning of their cocoons occupies scarcely over 

 three-quarters of an hour, often less. Reaumur, Vol. 2, p. 422, gives an 

 excellent description of the manner of spinning the cocoons. 



The number of parasites reared from a single caterpillar varies greatly. 

 The smallest number that I have reared was sixteen, and the largest was 

 fifty-two. Bignell reports having reared one hundred and forty-two from 



