1970] 
Eberhard — Wasps 
245 
retreat, climbed around to one end, curled her abdomen forward 
under herself, and moved in. Almost immediately the spider fell 
backwards out the other end, descended to the floor (these observa- 
tions were made on a porch), and began to crawl away. The wasp 
flew out of sight for about 30 seconds (perhaps disturbed by my 
presence, see below), then came back (I assume it was the same 
wasp), flew to the spot directly below the retreat where the spider 
had landed, and ran around quickly in that area. I could not discern 
any pattern in the search except that the wasp quickly began search- 
ing farther and farther from the original area. By the time the wasp 
had returned, the spider was about 0.5m away and climbing along 
the wall under the edge of the second row of shingles. The area of 
the wasp’s hunt quickly expanded to include the wall, and after about 
1 5 seconds she moved straight toward the spider which was about 1 m 
away now. She grabbed the spider with her legs and stung it once 
on the ventral side of its cephalothorax as soon as she reached it. 
The spider showed no defense against the wasp’s attack. It stopped 
moving as soon as it was stung, and the wasp grabbed it near the 
base of one leg with her mandibles and began drawing it up the 
wall. 
Wasps with spiders always moved backwards, dragging the spider 
behind them, and several wasps showed strong tendencies to drag 
their spiders upward. This behavior was probably preparation for a 
flight with the spider. One wasp was observed flying with a spider, 
and judging from the angle of its flight as it came to earth, it must 
have climbed at least 10 m up a tree that was 15-20 m from the 
site where it landed. 
Each wasp dragging a spider paused periodically, released her grip 
on the spider and flew around for a short while, then returned and 
dragged the spider onward. When I moved the spider a short distance 
while a wasp was gone on one of these short excusions, the wasp 
returned to the spot where she had left the spider and ran around 
quickly (again I could see no pattern) in that area. When she re- 
encountered the spider she stung it on the ventral side of its cephalo- 
thorax. This experiment was repeated several times, and even though 
the wasp encountered the spider from a different direction each time, 
she always stung it in the same region. The stinging was evidently 
released by the change in the spider’s position, since wasps did not 
sting spiders which had not been moved. This behavior may normally 
occur when a wasp fails to completely paralyze a spider with her 
first sting. 
