FOIIKST SUKl.I.-WASl' 4'n 



slender needle I stal) tlie cejjlialotliorax in two phiees, once 

 IVom al)()\c, oiK'f from below. My object is to reacb tbe 

 iianii'lions mentioned above, tlierebv in')nrin<>- tlieiii with in\- 

 needle and pro(lnein_i»' a soit of* j)aralysis in the spidei-. The 

 experiment works well enough. The vietini (juivers for a 

 moment, tlien lies motioidess. With my ernde stin<>-, repre- 

 sented by the needle, I have imitated as closely as possible 

 the metliods em])loyed by the parent wasp in preparini»- food 

 for her oft's])rin«4". 



Now 1 place the spider in the cell jnst under the sus- 

 pended unhatclied egi'; of the was}) and await developments. 

 In two days the young- wasp emerges from the shell, and 

 hangs head down, still attaclied at its anal segment to the 

 cell wall. For several hours 1 keep close watch, during 

 which time it pays no attention to the paralyzed spider. It 

 scorns my w^ork and the repast I have prepared and hangs 

 helplessly, its mouth sucking rythmically at the air. Now 

 I move the spider so that one of the stab wounds in its body 

 comes in contact with the larva's mouth. It responds fran- 

 tically, like a creature dying of thirst, to the li(juid that oozes 

 from the wound. It fastens itself by the mouth to its victim 

 and there it clings like a suction pad, its entire body rippling 

 as it drains the spider's life. 



^luch to my surprise the experiment is crowned with 

 success. In a few hours a change is noticeable in the larva — 

 it has grown and gained in strength. At length it pulls 

 away from the w^alls of the cell and settles among the spiders 

 I have provided. It is an experiment especially prolific in 

 answering abstract cpiestions and suggesting others. It 

 proves that all larva are not entirely dependent on one cer- 

 tain article of diet. Doubtless a given species is invariably 

 supplied by the parent with the same kind of food, yet we 

 have positive proof that such a condition is not imperative. 

 The larva has no more ahhorrence for the spider than for its 

 natural diet of caterpillars. If the mother wasp but knew 



