50 Some Solitary Wasps of Texas. 



latter developed normally. It hatched and the larva in due time 

 devoured every trace of the spider. August 8 it spun a fine white 

 cocoon, which, it might be added, never changed its color. This is 

 also true of the cocoons of A. suhcorticalis. The larva succeeded in 

 spinning its cocoon with support only from the low sides of the 

 broken cell. It is also significant that the larva and pupa both 

 developed quite as well in the light and without the protection of 

 the mud cell, also in the dry atmosphere of tlie laboratory, as they 

 would have done in their natural haunt on the banks of Waller 

 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- 

 nia's 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. suhcorticalis was running 

 along in a hop-step-and-jump 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 suh- 

 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 suhcorticalis 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 suhcorticalis goes a step farther and not only closes each one 



