270 
Psyche 
[Vol. 95 
a leg or pedipalp as she searches for the web, or she may leave the 
spider and make small forays. Once she has found the spider’s web 
or the vacant web of another spider, she inspects it thoroughly, then 
returns to the spider. Because the spider usually drops to the ground 
after it has been paralyzed, it is often necessary for the wasp to drag 
the spider, which may be much larger than she, up vertical surfaces. 
Although this species of wasp lacks strongly curved tarsal claws, she 
seems to have no difficulty finding purchase, probably because she 
is supported by large tarsal pads, not only on the last tarsal segment, 
but on all the others as well. 
The wasp may spend many minutes entangling the spider in the 
web, sometimes removing the spider from the web after a prolonged 
effort, only to begin over again. The spider is dragged into the 
densest part of the web, tangled extensively, and, with rapid pawing 
movements of one foreleg, the wasp attempts to draw loose strands 
over the spider. In the laboratory the wasp larva develops normally 
on a spider removed from the web and placed on a flat surface, but 
in a natural situation a spider that fell from the web would quickly 
be attacked by ants and other scavengers. 
Before ovipisition A. azureus straddles the spider and makes 
rapid thrusting movements with the tip of her gaster along the 
abdomen of the spider where the egg is to be laid. The effect of these 
movements is to shave all the hairs from an oblong area, usually 
about 2 mm long. An egg about 1.5 mm long is attached to the bare 
spot (Fig. 3A). This bare spot allows secure attachment for the egg 
and provides the newly hatched larva with an initial feeding site. In 
many species of Pompilidae the tip of the gaster is used for such 
tasks as tamping soil on the burrow entrance or trowelling mud 
(Evans 1963); depilation of prey can now be added to the list. Depi- 
lation of a spot on the spider’s abdomen may not be unique to A. 
azureus; such behavior in most other pompilids would occur in the 
concealment of a cell. 
Morphological Adaptations Associated with Hunting 
A. azureus has apparent morphological adaptations that suggest 
it has a long evolutionary association with Filistata. Compared to 
most other members of the Pompilini, such as species of Anoplius 
and Poecilopompilus, the body of Alio chares is elongate and 
