CHAPTER VI 

 SOME MUD-DAUBING WASPS THAT HUNT SPIDERS 



Sceliphron (Pelopoeus) caementarium Drury. 



In a former study 1 of the contents of the nests of this 

 species we included many items on the behavior of this 

 insect. We present here a few notes on the biology of this 

 species, not included in those pages. 



We learned in the previous observations that the mother 

 sometimes fails to supply sufficient food for the growth of 

 the young, but we did not inquire whether the larvae could 

 assimilate more than the normal amount of food supplied by 

 the mother. The number of spiders most frequently supplied 

 by her is six or seven. In the one case in which we experi- 

 mented upon this point, we added three more spiders ; these 

 were promptly devoured, so we added one more. By the 

 next evening this too was gone, so we gave the young wasp 

 four more fat ones. Two of these were eaten, and the larva 

 was found dead. Whether its gluttony produced its death 

 we do not know, but in the five days it had eagerly con- 

 sumed six extra spiders. 



During the latter part of June we had the good fortune 

 to discover three Peiopoeus larvae in the act of pupating. 

 This enabled us to learn accurately the duration of the pupal 

 period at that time of year. One of them emerged nine- 



Animal Behavior 6: 27-63. 1916. Also Journ. Animal Be- 

 havior 5: 240-249. 1915. 



118 



