64 
Some Solitary Wasps of Texas. 
Creek. The adult, a female, emerged August 23, just twenty-two 
days less three hours after the egg was laid. The adult from cell 
No. 2, also a female, emerged by a small round hole in the side of 
the cell on August 22 and the total length of its development was 
twenty-three days. On August 16, nineteen and one-half days after 
it was stored and closed, the oldest cell brought forth thirty to 
thirty-five parasitic wasps of the species mentioned above. Age- 
niafs cocoon was present but its contents had been devoured by the 
larvae of the nefarious swarm which darted around on the inside 
of my collecting bottle clamoring for exit. 
My first acquaintance of the species A. subcorticalis was running 
along in a hop-step-and-jtimp fashion carrying in her mandibles a 
large legless Attid. She ran up a tree for a foot and dropped her 
burden to the ground. Before she could recover it another sub- 
corticalis was on the scene and a struggle for the spider ensued. 
The intruder caught it up and ran with it into a crevice in a tree 
as if to hide there. . But the rightful owner recovered her quarry 
and made away with it in all haste, mounting a slender sapling to 
the height of twenty feet, and was lost to view. The other wasp 
continued her search for a while but she too soon disappeared. 
Spiders are not the only creatures that will occupy the abandoned 
cells of an old mud-dauber’s nest. Trypoxylon finds them a very 
convenient abode (Fig. 23) and even the graceful and handsome 
Agenia subcorticalis will not disdain to build her little cells and 
rear her young where an inferior Pelopoeus has been born. Try- 
poxylon uses the whole lumen of the empty cell as it is, merely 
closing the opening after the cell is stored. But Agenia uses the 
cells merely as cavities in which to build her own small cells of the 
ancestral type. Thus she may have as many as five of her own mud 
cells inside a single chamber of the big mud-dauber’s nest. In- 
deed subcorticalis goes a step farther and not only closes each one 
of her own individual cells but builds a plug over the opening to 
the large chamber just as the original proprietor would have done, 
thus offering an additional rampart to her enemies. 
The dirt which Agenia uses is taken from the very nest in which 
she is building her own. This makes it very convenient for her, 
of course. She gnaws off her pellets, moistening the dirt as she 
works. As I have observed in the case of Trypoxylon the supply 
of water necessary for moistening so large an amount of dry dirt 
must soon give out. So after a number of trips Agenia , like 
Trypoxylon , flies away to get a drink of water and then returns 
to resume her work. She wisely economizes in her use of water 
