PARASITE APANTELES ACHERONTI^. 19 



NOTE ON THE PARASITE APANTELES ACHERONTliE OF 



THE CATERPILLAR OF THE " DEATH'S 



HEAD" MOTH. 



By E. Ernest Green. 



With a figure. 



THE huge caterpillars of the " Death's Head " moth occur com- 

 monly upon the " dadap " tree {Erythrina lithosperma) , and 

 might become a serious pest if they were not kept in check by the 

 parasite described abov^e by Mr. Cameron. This parasite is of almost 

 miscroscopic dimensions, being only one- tenth of an inch long ; but 

 makes up for its minute size bj^ the enormous number of individuals 

 that infest a single caterpillar. It is probable that fully seventy-five 

 per cent, of the caterpillars are infested and ultimately killed by the 

 parasites. They feed inside the body of the unfortunate victim 

 until it is fully grown. The caterpillar then suddenly becomes 

 flaccid, and hundreds of tiny grubs make their way through its 

 skin and spin the remarkable compound cocoon — resembling a 

 mass of white cotton wool — that may frequently be observed 

 attached to the leaves of the dadap tree. The empty carcase of 

 the caterpillar usually falls off, and leaves no clue to the origin of 

 the cocoon. Though externally appearing homogeneous, this mass 

 is composed of separate cocoons surrounded and bound together 

 by loose woolly matter. The resulting insects are minute black 

 wasps. 



From the smaller cocoon shown in the figure, 1,226 of these tiny 

 insects emerged, and others (probably several hundred more) failed 

 to extricate themselves from their woolly covering. It can scarcely 

 be supposed that this number represents the progeny of a single 

 parent. It seems probable that the insects attack the caterpillar 

 en masse. 



Mr. Cameron describes the compound cocoon as being attached 

 to a twig by a peduncle, but this is not usually the case. The larger 

 cocoon represented in the figure is closely attached to the leaf for 

 its whole length, and this is the more common formation. The 

 mode of attachment naturally depends upon the position occupied 

 by the caterpillar at the time of its death. 



