164 
The Ohio Naturalist. 
[Vol. X, No. 7, 
disturbed appearances. Whenever the nest is entered the 
opening is likewise always closed up from the inside. 
These observations were made on August 18 and 19, and 
although many burrows were opened only 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 only 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 by 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 
helieis. 
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. 
