MUD-DAUBING WASPS 125 



wasp, who would easily free herself from the web and 

 chase the spider to its retreat." We have never witnessed this 

 method of almost human cunning and deception, but we are 

 sure that not every wasp could easily extricate herself from 

 the web, for in four instances, at different times and places, 

 we have removed from spiders' webs the dead remains of 

 C. caeruleum. 



We noticed one C. caeruleum flying and buzzing from place 

 to place on the barn wall. We lost her for a moment, but 

 when next seen she had a small spider in her mouth and had 

 her abdomen flexed to sting it. She alighted near by and 

 it seemed she was turning it over and over in her mouth, per- 

 haps eating it, or adjusting it for stinging. She eluded close 

 watching, so we could not observe the details of her habits. 



The season for C. caeruleum is long. The extreme dates 

 on which we have thus far observed them cut were May 20 

 and October 13. They were seen in July and August, feed- 

 ing on the flowers of Pinipenella. 



A more complete account of the work and behavior of 

 this wasp may be found in our paper on The Biology of 

 Mud-daubing Wasps, 12 with a description of the cocoon 

 made by the larva recorded in a separate note. 13 Figure 30 

 illustrates the interior and exterior of their nests. 



These wasps, while they are solitary in their mode of life 

 by day, are gregarious at night, and congregate, night after 

 night, at a chosen spot for the purpose of commingling in 

 sleep. The full account of this strange habit may be found 

 in our paper on The Sleep of Insects. 14 



12 Journ. Animal Behavior 6: 27-63. 1916. 



13 Psyche 22 : 62-63. 1915. 



14 Ann. Ent. Soc. Amer. 9: 227-275. 1916. 



