126 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.52. 



them in a breeding cell in the basement of my home. The egg of 

 the wasp did not hatch until on June 20, delayed, no doubt, by the 

 low temperature of the room, and the larva died on June 21. On 

 June 23 I removed the dead larva and pinned the fly. This fly 

 was not dead at the time it was pinned and even after the pin had 

 been thrust through the thorax it continued to move its antennae 

 and its legs. In this case a fly paralyzed by B. spinolae lived for 

 10 days and might have lived longer had I not killed it. As will be 

 pointed out farther on the first fly brought to the nest by spinolae 

 supports the egg of the wasp until it hatches. Furthermore, so far 

 as my observations go, this fly is not consumed by the larval wasp. 

 If this fly was dead at the time the egg is laid upon it, placed as it is 

 in the warm moist earth, it would in all probability decompose before 

 the egg would hatoh and would prove a very unsatisfactory foundation 

 for the support of the larval wasp. In no case where I have taken 

 the fly from the nest within twenty-four hours after the egg was placed 

 upon it has the fly failed to respond to stimulation. All were para- 

 lyzed. Just how long they remain in this state in the burrow before 

 death ensues I cannot say. Many of the flies brought in by spinolae 

 for the developing larva are dead but by no means all of them. I 

 frequently found in brood chambers, containing half grown larvae, 

 flies that responded readily to stimulation. The Peckhams also 

 report two instances in their observations on spinolae in which the 

 fly brought in was not dead but paralyzed. 



With regard to the European species B. rostrata, which Fabre 

 and Wessenberg-Lund had under observation, I, of course, have had 

 no experience, and the fact that B. spinolae can and does make use 

 of her power to paralyze is not a proof that B. rostrata does likewise. 

 Lepeletier maintains, as pointed out above, that rostrata does paralyze 

 her prey and it is possible that both Fabre and Wessenberg-Lund 

 failed to carry the investigation far enough to discover the whole 

 truth. Be the facts in the case of rostrata what they may, Wessen- 

 berg-Lund's conclusion that the form of the abdomen of Bembix 

 inhibits the power to paralyze can not be accepted; for, in the case 

 of one speoies of Bembix and of two species of Bicyrtes, in which 

 genus the form of the abdomen is almost identical with that of 

 Bembix, we know the prey is paralyzed. Furthermore, Hartman, in 

 his Observations on the Habits of Some Solitary Wasps of Texas 

 (page 30), reports an observation on Bembix texana Cresson, in 

 which the wasp seized and stung a fly that he had caught and 

 fastened down for the express purpose of observing this action on 

 the part of the wasp, and the Peckhams in their observations on 

 Bembix spinolae report that they twice observed this species in the 

 act of stinging a fly. 



