297 



concentrate more of her efforts toward the thorax and head, 

 two or three times she worked abont the head as if attempt- 

 ing to sting there, while the Prosoplus attempted to grasp the 

 end of her abdomen. At length the strnggles of the Prosoplus 

 grew weaker and weaker and she was able to pursue her work 

 more easily and could occasionally clean away the wood dust 

 which had accumulated on her body. She proceeded to the 

 anal extremity of the body and carefully and deliberately 

 stung in the sutures there two or three times near the lateral 

 margin and then worked her way along the body, inflicting 

 a sting apparently wherever she could get a response to her 

 g-nawing the surface, working along thus to the head. By 

 this time the larva was practically immobile and from time 

 to time she would rest and bite at the cuticle in feeding. 



I did not time this struggle but it must have continued 

 twenty minutes or more and at its conclusion the Prosoplus 

 larva was completely immovable and did not struggle at all 

 when she fed in the usual manner of her kind. 



Conflict of Sclerodermus chilonellae with its Picij. This 

 species is much larger and stronger than >S'. im migrans and at- 

 tacks the vigorous woodboring larva of Hyposmocoma chilon- 

 ella. Three females were bred from cocoons brought in from 

 rotten wood of Pipturus in which were many larvae of this 

 moth. A larva was placed with these three females and a 

 male on July 7, and on July 10, the larva was seen to be 

 paralyzed and was completely sucked dry. Another larva 

 placed with them on the same day Avas paralyzed on July 

 12, and completely sucked dry by July 1-1. 



One female and the male were separated and placed with 

 a large Hyposmocoma rliilonella larva, l)y which the male 

 was soon killed. The other two were placed with another 

 Ilyposmocomu larva about 20 mm. long and they proceeded 

 to attack it jointly, their bodies straight and backing up to 

 sting. They were exceedingly active on their feet, dodging 

 the attacks of the Hyposmocoma. the latter l)eing very aggres- 

 sive in its efforts to bite the end of the abdomen of the 



