36 IMPORTED PARASITES. 



Tachinid parasites, except the Japanese Crossocosmia, which 

 is nearly so difficult to handle. 



Multiplication of this parasite in the open, under favorable 

 conditions, which it is believed the present season offers, ought 

 to be exceedingly rapid. As in so many other instances, the 

 year to come is crucial, and will likely demonstrate the ability 

 of this species to become Americanized. 



Success with Blepharipa, and its rapid acclimatization in 

 America, is looked for more especially on account of the close 

 correlation which exists between the parasite and host. Like 

 Anastatus, this correlation is perfect, and the parasite is able 

 to continue its existence from year's end to year's end, inde- 

 pendent of any other insect. This, in connection with its ex- 

 traordinary powers of multiplication, make it one of the most 

 promising of the parasites studied at the laboratory, and perhaps 

 the most promising of all. 



Compsilura concinnafa. 



Only a very few of the introduced parasites are equally im- 

 portant as enemies of both the gypsy moth and the brown-tail 

 moth, although a number of them are known to attack both to a 

 varying degree. One of the few which are important enemies 

 of both is Compsilura, a Tachinid fly like Blepharipa, but dif- 

 fering from that species in a great many important particulars. 

 Instead of depositing eggs on the foliage, to be eaten by the cat- 

 erpillars, the eggs hatch, in the body of the parent female, and 

 the minute maggots are thrust beneath the skin of the host after 

 a fashion somewhat comparable to the manner in which Glypta- 

 panteles deposits its eggs in the active caterpillars. Usually 

 only one parasite develops in one host. 



The maggots begin to feed at once, and in a very short time 

 (less than two weeks in the summer) are full fed, and have 

 caused the death of the host caterpillar. They then work their 

 way outside of its body, drop to the earth and transform to pu- 

 paria, from which shortly after the adult flies issue. 



Since the parasite has been secured in both brown-tail and 

 gypsy moth parasite importations, the numbers which have been 

 received and liberated have been considerable. The first col- 

 onies were planted in 1906, and in each year since, but partieu- 



