WASPS, SOCIAL AND SOLITARY 



We are not as familiar with the habits of T. bidenta- 

 tum as with those of the other two, but we have a few 

 notes relating to the female. This little worker is the 

 smallest of the three, and like her sisters is a confirmed 

 spider- hunter. Once, when out among the raspberry 

 bushes, we had the good fortune to witness a capture. 

 The wasp seized the spider, as it rested on a leaf, by the 

 top of the cephalothorax, and, holding it firmly, curved 

 her abdomen under and stabbed the ventral face of the 

 cephalothorax. All her motions were deliberate, and 

 after the operation she delayed a moment before picking 

 it up by a leg and flying off. We often found raspberry 

 stems which had been filled with spiders by this wasp, 

 but we do not know the length of time required for the 

 development of the egg, nor how long the larva eats be- 

 fore pupation. The cocoon is very different in appear- 

 ance from those of rubrocinctum and albopilosum, be- 

 ing exceedingly long, slender, and almost white, instead 

 of short, wide, and brown. The perfect insects come 

 out in September, and the last cocoon formed is the first 

 one to hatch. This was also true of the cocoons of 

 rubrocinctum formed in straws. 



Years ago, when we found that many of the orb- 

 weavers laid enormous numbers of eggs (A. cophinaria 

 from 500 to 2000), we wondered what became of the 



194 



