1934 ] 
Biological Notes on Sphex wrightii 
157 
on the lateral surface of an abdominal segment found in 
a shallow cell not far below the surface. Before the egg had 
the opportunity or time to hatch in my office at the Univer- 
sity, it was found that fly larvae had taken their toll. Inter- 
nally, they had eaten the food to the extent that the body 
walls of the moth larva collapsed and the wasp’s egg per- 
ished. The identity of the three larvae, which each formed a 
puparium, was not learned. In later emerging from the 
puparia, they crawled into the cotton about them before the 
body parts were normally expanded and fully developed, 
thus preventing accurate comparison with normal flies and 
correct identity. 
This wasp species did not use a tool at any time as the 
tool-users do, although it worked on the large pebble, trying 
again and again to force it farther into the tunnel and re- 
peatedly vibrating it. This last record, however, is prob- 
ably not typical and complete, since the ants disturbed the 
nesting wasp and probably abbreviated many, if not all of 
her activities. 
The larger ant, which troubled the wasp, was taken, and 
has been compared with determined specimens in the col- 
lection of the University of Colorado. It is possibly a vari- 
ety of Formica fusca L. It was very pugnacious, actually 
throwing itself at the wasp, which it may have “thought” 
to be an oversized ant and may have resented its intrusion 
in this territory. It is possible, too, that the ant was trying 
to obtain the prey of the wasp as food for its own nest. 
The writer is indebted to Charles R. Bitter for the photo- 
graph of the cocoon of this wasp and to Louise Ireland for 
the drawing of the larva. He is pleased to express his 
thanks for this help, as also to Professor Fernald for the 
determination of this wasp and references to this and other 
digger wasps. 
