THE BEMBICENE WASPS 17 



At 2 130 in the afternoon of the second day all the excite- 

 ment was gone, and all was quiet excepting a half-dozen 

 or so females which were beginning to dig their nesting- 

 burrows. All of our afternoon observations show that the 

 mating flights occur only during the morning. 



Every morning, for ten days, we found Bembix in the 

 field in the characteristic flight, but as the days passed, the 

 number of those in the sun-dance became less and less while 

 the number of females busily burrowing increased propor- 

 tionately, until July 14 when the dancing behavior ceased. 

 During the latter part of this period, only an occasional 

 mating was to be seen. What becomes of the males? Do 

 they fertilize the females once for all and promptly die, 

 or do they hide away among the grass to be at hand when 

 needed? We suspect that the former condition holds, for 

 we have never found Bembix males in the grass or any- 

 where except for this one occasion, and I have never seen 

 these wasps mate while nest-building. 



Thus it seems that the one gala day which we so for- 

 tunately witnessed was not only the first but also the chief 

 festivity of the BembLv year, for, although we saw a cer- 

 tain amount of this behavior on subsequent mornings, we 

 never again saw the whole population give itself up to the 

 dance as on this first occasion. After this had waned, only 

 a few wasps were to be found above ground at a time. We 

 do not know whether the males had migrated or perished, 

 but we have every reason to believe that a large number of 

 females were busy working in their underground nests or 

 foraging for food for their young, so that now only a small 

 proportion of the population at a time was in evidence above 

 ground. 



The work of most of our solitary wasps in nest building 

 is characterized by an admirable constancy and zeal, but 

 some labor with calmness and patience, and some even so 



