344 
Psyche 
[June 
Studies over the next few days revealed that most females cleaned 
the cells of uneaten prey or pieces of prey each morning before they 
began provisioning. Wasps backed out of their burrows, holding the 
debris in their mandibles, then flew off 2-6 m, ascending to a height 
of 1-2 m, and dropped it on the ground. Many females flew over a 
nearby hedge and dropped their load on the other side. It appeared 
that smaller pieces of prey were dropped closer to the nest than 
larger ones (sometimes whole, uneaten flies), although we have no 
quantitative data to support this. Cell cleaning usually required only 
5-8 minutes, during which time 3-6 loads were carried from the nest. 
The following notes on one nest (HEE, C55-2) may serve as an 
example. 
This female first entered her nest at 1106 hours, clearing the 
entrance as she entered. After a minute or two she backed out with 
a large, whole fly which she carried on the wing a distance of 4 m 
and dropped. She returned to the nest quickly, this time remaining 
inside only 10 seconds and emerging with a fly which she carried 
6 m and dropped from a height of 1.5 m. On the next trip she re- 
mained in the nest 10 seconds and emerged with a small particle 
which she dropped 3 m away from a height of 1.5 m. On the fourth 
and final trip she remained in the nest 8 seconds and emerged with 
a very small particle which she dropped quite close to the nest. She 
then returned to the nest, closed the entrance (having left it open 
while cleaning), and flew off at 1114. She returned with her first 
fresh prey at 1 1 1 7. 
We did not observe cell cleaning at Santa Maria or Las Termas, 
Argentina, but our observations were not prolonged in either site, 
and were mostly made in the afternoon. Most of the nests we ex- 
cavated at these sites contained little debris, strongly suggesting that 
cell cleaning had occurred earlier in the day. We are under the 
impression that cell cleaning is a common feature in populations in 
western Argentina, as it evidently is in the Buenos Aires region 
(Brethes, 1902; Llano, 1959). 
Final Closure 
Several final nest closures were observed at Cali, Colombia. In 
each case the female emerged from the entrance repeatedly while 
scraping soil behind her; she often moved as much as 4 cm away, 
scraping soil into the hole, then either backed in or turned around 
and walked to the burrow, turning around in the entrance and back- 
ing in. In no case were females seen to take flight and land in the 
