24 WASP STUDIES AFIELD 



which, like the new habit just described, would go entirely 

 outside the genus Bembix. We know that the digger wasps, 

 Bembix, Amnwphila, Priononyx, are essentially diggers, 

 but Dr. Parker finds the Bembix in his colony taking up 

 mason work also, building partitions to form new cells. 

 "A wall is placed across the chamber and another larva 

 reared between this and the main part of the burrow." It 

 seems incredible that nubilipennis could build the wall of 

 dry sand or dust, unless she too has acquired the water- 

 carrying habits of certain Odynerns. The fillings of loose, 

 dusty earth, such as she scoops into her holes here, could 

 never be made to serve as a wall across the bulging middle 

 of the chamber. It would be well worth while to make an 

 effort to see how general this new habit has become. 



W r e have so many times found the mother Bembix in her 

 burrow when we opened it at any time near or after sunset 

 that we have arrived at the conclusion that she sleeps in 

 her nest, when 'she has one. We have also found her here 

 safely hidden away on dark or rainy days, for Bembix 

 loves only warmth and sunlight. The tunnel is always tem- 

 porarily closed under these conditions. This is accomplished 

 by the Bembix going down into the hole and pushing up 

 loose dirt from below until the mouth of the burrow is com- 

 pletely closed. One morning we found that the dashing rain 

 during the night had packed the soil hard and washed down 

 the loose earth, leaving the hole open. We arrived just in 

 time to see the mother Bembix cutting a small area about 

 the opening and kicking the dirt thus loosened into her bur- 

 row until the aperture was closed. It seemed that this 

 mother had remained in her burrow all night, with only the 

 usual temporary covering over it, and that the rain had 

 washed down this dust covering and she, unwilling to have 

 herself and her nest exposed thus to danger, was hastening 

 to cover her burrow again, even though she had to dig up 



