36 WASP STUDIES AFIELD 



Our present evidence indicates that there is only one gen- 

 eration per year of B. nubilipennis. From the time of 

 emergence, in June or early July, the females go on with 

 nidification until the middle of September. We do not know 

 how many nests each constructs during this season, but they 

 ought to make several in order to offset the high mortality 

 and keep up so large a population. The numbers gradually 

 diminish as autumn approaches; since we never see them 

 elsewhere hereabouts, we conclude that the mothers grad- 

 ually die off. They spend the winter in the pupal stage and, 

 despite the fact that they reach this stage at different dates, 

 they all emerge simultaneously when the warm rays call. 



The persistence with which BembLv adhere to the one 

 location which we have watched year after year is astonish^ 

 ing. Truly, their dissemination seems to be nil. In regard 

 to this species at least, one is soon ready to agree with the 

 Peckhams in their opinion that wasps generally do not travel 

 far from the place of their birth. Here the wasps of our 

 particular colony have had at their disposal a pasture equal 

 in size to six city blocks in which to choose their nesting- 

 site, yet year after year they limit themselves strictly to two 

 distinct corners of a base-ball diamond, in the middle of 

 this field. Here they suffer weekly, and sometimes daily, 

 persecutions under the spiked shoes of the boys; they are 

 routed from their work in the middle of the day and their 

 nests are obliterated in the powdered earth, and riot a few 

 must suffer death in the melee; yet not even this pressure 

 causes them to move twenty-five feet to one side, where 

 they might enjoy peace and prosperity. The fact that each 

 successive generation should show the same choice and the 

 same persistence is all the more astonishing. In another 

 vacant lot a mile away was another colony which, to our 

 knowledge, persisted in like manner on a small area for 

 three years. Finally a building was erected on the site and 



