242 



PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 



Fig. 45. — Chalcis flavipes: Female. 

 Hind femur and tibia, showing 

 markings. Greatly enlarged. 

 (From Crawford.) 



ment of pupae from Japan, but the exact localities from which these 

 shipments came is not known. 



Both are, or appear to be, invariably solitary, notwithstanding 

 that there is an ample food supply in one pupa for several individuals. 

 Invariably there is an abundance of unconsumed matter in the host 

 pupa, and on this account the parasite has rarely been successfully 

 reared from any of the imported pupae except the small males, in 

 which this matter is in such small amount as partially to dry before 



receipt at the laboratory. In the large 

 female pupae the decomposing contents of 

 the pupal shell form a semiliquid mass, 

 which is shaken about while the material is 

 in transit, and completely overwhelms the 

 larva or pupa of the parasite. The parasite 

 is able to withstand this condition to a re- 

 markable extent, but not to the extent fre- 

 quently brought about by the unnatural 

 conditions incident to transshipment. 



Partly on this account, but still more 

 owing to the difficulties which have stood in the way of securing an 

 adequate supply of gipsy-moth pupae in good condition from localities 

 where Chalcis occurs, it has not yet been possible to colonize either 

 the European or the Japanese species satisfactorily, nor, so far as 

 known, successfully. Only a few hundred have been received, all 

 told, since their status as primary parasites 

 was first established in 1908. Had they all 

 been of one species, received at one time, 

 and colonized in the same place, there would 

 be some reason to expect that the coloniza- 

 tion would be followed by establishment. 

 There were two species, however, they were 

 not all colonized in one place, and coloniza- 

 tion has extended over three years. The 

 best and largest colony was liberated in 1909 

 and strengthened by the addition of the 

 small number received from abroad in 1910. 



A single specimen was reared from a lot of gipsy-moth pupae col- 

 lected in the immediate vicinity of the colony shortly after it was 

 founded in 1909, but none issued from similar collections made in 

 1910. 



Both Chalcis flavipes and C. obscurata have been carried through all 

 of their transformations in the laboratory on American pupae. The 

 females are able to oviposit very shortly after emergence, and will do 

 so with considerable freedom in confinement, making possible the 

 artificial multiplication of either species were it possible to secure a 



Fig. 46. — Chalcis obscurata: Fe- 

 male. Hind femur and tibia, 

 showing markings. Greatly en- 

 (From Crawford.) 



