1 64 The Ohio Naturalist [Vol. X, No. 7, 



disturbed appearances. Whenever the nest is entered the 

 opening is hkewise always closed up from the inside. 



These observations were made on August 18 and 19, and 

 although many burrows were opened onh' larvae were found. 

 Many of these had completed their growth and were encased in 

 cells of earth held together by some cement substance and lined 

 inside with delicate silk ; but in every instance an immature larva 

 in some stage of development was also found in the burrow. In 

 no case, however, was more than one developing larva found in 

 any burrow. In one burrow with four branches there contained 

 matured and encased larvae and the fourth, just newly con- 

 structed, contained two recently killed house-flies, on one of 

 which was found an unhatched egg. From the data given above 

 it would appear that the wasp rears onlv one larva at a time, 

 unless perchance she constructs and attends two or more burrows 

 at the same time, the necessity for which is not apparent. 



The food of the larva, as shown by the nests opened, consists 

 wholly of flies and it seems that certain females show a preference 

 for a particular kind of fly. In one nest only house-flies were 

 found; in a second the majority were stable-flies; in a third, 

 flesh-flies; in a fourth, tachina-flies. The wings, legs and usually 

 the thorax of the fly are not consumed by the larval wasp. The 

 remains of forty-one flies, of which most, perhaps all, were 

 house-flies, were taken from a chamber containing an almost 

 mature larva, and doubtless these were not the total number of 

 flies consumed b}" this individual. In the evening from a cham- 

 ber containing a half-grown larva ten untouched flies were taken, 

 among which were represented the following species kindly 

 identified for me by Prof. J. S. Hine: Euphorocera claripennis, 

 Pseudopyrelia cornicina, Sarcophaga assidua, and Sarcophaga 

 helicis. 



According to my limited observations all burrows containing 

 immature larvae are closed up at nightfall with the female inside 

 the nest. The popular belief is that the male closes up the 

 burrow from without after the female has entered the nest for the 

 night, but I saw nothing that would tend to confirm this opinion. 

 The lad that helped me to open the burrows stated that he had 

 often drowned the wasps out of their nests and that he usually 

 chased two out of each nest. From the manner in which he 

 described the proceedings I fear the fun he got out of the opera- 

 tion is more worthy of credence than is the accuracy of his 

 observations, for in no instance did I get more than one wasp 

 from a burrow and all thus taken were females. Unfortunately, 

 I had no net with me and hence was unable to determine whether 

 any males were among the numbers that were continually darting 

 about over the nesting site, though I suspect that such was 

 the case. 



