THE BEMBICENE WASPS 35 



ing and capable of consuming even a larger amount of food 

 than the mother provides. 



The larvae kept in tin boxes or in vials were unable to 

 spin the usual cocoon, owing to the fact that there was no 

 dirt to blend with the silk. The pupal cases spun in the 

 natural habitat are hard, tightly woven cocoons made of 

 silk blended with earth. (See fig. 6 b, c, d.) 



In keeping Bewibix pupal cases at home we often found 



FIG. 6. The cocoons of Bembix nubilipennis. Exact size, a, abnormal 

 cocoon ; b, normal one ; c and d, empty cocoons showing apertures 

 made by emerging wasps. 



the organism within infested by the tiny Hymenopterous 

 parasite Melittobia sp. These no doubt had escaped from 

 some Pelopoeus nests in the same room, and very probably, 

 under natural conditions, B. nubilipennis is not pestered by 

 them. One Bembix burrow was observed which was nor- 

 mally filled in, but many ants were coming and going 

 through the small passageway which they had made through 

 the loose dirt. When this nest was opened it became ap- 

 parent that they were after the debris of dead flies wings, 

 heads, legs, etc. The wasp larva had pupated, unharmed, 

 but the musty debris was alive with two species of mites. 

 Dipterous parasites shadow Bembix, and a small female 

 Mutillid abounds in this area, but neither of these has been 

 seen to actually enter their holes. 



