1965] 
Evans — A?nmophila azteca 
15 
Powell (1964) found a lycaenid larva to be used in Baja California, 
while in Mono County, California, a larva of the moth family 
Pterophoridae was employed. As Powell points out, lycaenid larvae 
are covered with short, secondary setae, while pterophorid larvae 
have tufts of elongate setae. The caterpillars taken by Powell 
measured 14 and 15.5 mm in length, while those taken from the nest 
in Yellowstone measured from 8 to 15 mm in length. Thus it appears 
that size of the prey is of critical importance, but not its vestiture or 
taxonomic affinities. 
Powell reported that the lycaenid larva was carried in flight, about 
a meter above the ground. I observed prey carriage in flight once in 
Colorado and many times at Jackson Hole; in no case did I observe 
prey carriage over the ground. The female straddles the caterpillar, 
grasping it with her mandibles a short distance behind the head and 
during flight embracing the body of the caterpillar with her legs, the 
prey being venter-up. She lands a short distance from the nest and 
walks to the entrance, usually without circling or hesitation, then 
drops the caterpillar at the threshold while she removes the closure. 
At Jackson Hole, I experienced much difficulty approaching females 
closely for photography at this time; they would very readily take 
flight with their prey, often disappearing for several minutes. 
Removal of the closure occurs very rapidly, taking only a few 
seconds if it is an initial closure, generally less than 30 seconds in any 
case. Soil particles and objects removed from the burrow are deposited 
within a few cm of the entrance and may be reused when the closure 
is restored. When the burrow is clear, the wasp grasps the anterior 
end of the prey with her mandibles and backs into the nest with it. 
The entire process (arriving with prey — clearing entrance — draw- 
ing in prey — reclosing entrance) occurs with remarkable speed, some 
individuals requiring less than a minute. When it is considered that 
only from one to four prey are introduced per day, it will be appreci- 
ated that even prolonged periods of observation afford one only 
fleeting opportunities to study this behavior. 
In addition to entry with prey, each nest is entered periodically 
when the wasp is without prey. There are presumably “inspections” 
which function to impress upon the wasp the size and food require- 
ments of the larva, as Baerends (1941) found to be true in A. 
pubescens. Inspections may occur at any time of day, but most 
characteristically occur early in the morning (0830-1030). In fact, 
the first act of each Ammophila arriving in the morning consists in 
entering the nest and closing it again. I did not observe any one 
female inspect more than one nest at this time; apparently when there 
