72 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



case of species of Bembex and Bembidula. As a result the larva 

 makes a hole through the egg covering where this is attached 

 to the caterpillar and then through the body wall of the cater- 

 pillar. It then thrusts its head through the opening and begins 

 to feed on the internal parts of its victim. Thus the egg still 

 remains in place till the growing larva ruptures it and even then 

 it remains for a time as a collar about the larval wasp where it 

 enters the caterpillar. 



The young wasp does not change its position but remains with 

 its anterior end thrust inside the caterpillar, which contracts in 

 length as the feeding of the larval wasp proceeds. On the morn- 

 ing of the twenty-fifth the caterpillar had contracted considerably 

 (fig. 4) and the wasp had greatly increased in size. On the twenty- 

 sixth the caterpillar was entirely consumed nothing remained 

 but a few fragments of integument and the fully developed 

 larval wasp was spinning threads of silk over the sand in the 

 cell (fig. 5). At six p.m. of the twenty-sixth the larval wasp was 

 busily spinning its cocoon which was fully formed on the morning 

 of the twenty-seventh (fig. 6). 



The cell with its contents was placed in the sand in the garden 

 and was not again disturbed till September 7, when it became 

 R. cessary to transfer it to another place. To my surprise I found 

 that the adult had emerged in the cell and unable to escape had 

 perished there. The insect was badly decomposed and I should 

 judge that it had been dead for at least a week. 



Wasp No. 57 was observed July 27 busily engaged in digging 

 a nest and when this had been digged to the depth of about one 

 inch she suddenly backed out of the burrow and, if I may be 

 permitted the use of a vulgar expression, ' 'threw a fit." Appar- 

 ently she had bitten into something that was exceedingly ob- 

 noxious to her. She rubbed her mouth parts violently with her 

 front feet, twisted and contorted her body, bit into the stems 

 and leaves of the weeds about her and displayed every manifes- 

 tation of great distress. I got down quite close to her but could 

 discover nothing on her body or appendages that could be the 

 cause of her strange conduct. After some time she returned to 

 her unfinished nest but no sooner had she thrust her head into 

 the opening than another paroxysm ensued. This was less vio- 

 lent than the first. Again she returned to her nest but was 

 affected as before just so soon as she reached the entrance and 

 she then abandoned her task. 



Curious to know what had been the source of her discomfort 

 I digged down into the ground carefully following the opening 

 made by the wasp. At the bottom of it I found a living but 

 paralyzed caterpillar, the remains of a second one and the newly- 

 formed cocoon of a wasp, but not of this species. Mingled in 



