THE SPIDER-HUNTERS 



as her ancestors, and how should she guess that the 

 presence of a certain fly or wasp means danger to her 

 race? Of what happens to her egg after she leaves it 

 she is so absolutely ignorant that she might easily look 

 on with serene indifference at the destruction of her 

 own larva by that of the intruder. In Astata we see, as 

 might be expected, a calm tolerance of the visits of the 

 Chrysis fly, but the uneasiness of scelestus herself at 

 the sight of Ceropales and the valorous defense of Try- 

 poxylon show more highly developed instincts. Bem- 

 bex, too, deeply resents the presence of parasites, al- 

 though after the deed is done she feeds their young 

 without questioning their right to her care. Among 

 bees, Andrena, and Nomada, which is parasitic upon it, 

 are said to live on most friendly terms; but in other 

 genera there is a deep-seated enmity between host and 

 parasite. 



In the literature of the Hymenoptera references have 

 been made from time to time to certain wasps that cut 

 off the legs of spiders or other creatures before storing 

 them away; but observations on the subject have been 

 rare and not very definite. Brehm, in the "Thier- 

 leben," says that Agenia punctata builds nests of mud, 

 and places in each cell one moderately large spider 

 from which she has first removed all the legs. The 

 243 



