Some Solitary Wasps of Texas. 17 



observed by tbe Peckhams and Dr. Williston on Ammophila urraria 

 and Ammophila Yarrowi. In each of these two cases the wasp 

 used a pebble to tamp down and smoothe over the ground, not once 

 merely, but several times, laying the pebble aside each time while 

 she brushed on more sand. The use of the piece of wood by Amvio- 

 phila procera in a similar manner is not so decisive since she presses 

 a number of articles into the nearly closed entrance before she uses 

 the last piece in any way approaching its use as a tool. Perhaps the 

 use of the pebble by A. Yarrowi^ the prairie species, is an extension 

 of the more generalized habit of procera which lives in the woods 

 where rubbish of all kinds is easily accessible and the whole tunnel 

 is filled with it as shown in Fig. 18. 



After the nest has been closed and the tunnel filled flush with 

 the surface, sticks, whole leaves or blades of grass, etc. (things 

 are not too large now), are carried over the nest to obliterate all 

 traces of the wasp's work. In fact this is sometimes so skillfully 

 done that unless one makes a mark he fails to find the nest again 

 except by cutting vertical sections in the direction of the nest until 

 this is opened. 



The process of thus concealing the nest is, or course, highly pro- 

 tective to the human eye, though it can hardly be its real purpose 

 to delude man or to entertain an admiring observer. The habit 

 is probably a mere extension of the one which impels the wasp to 

 carry debris into the tunnel to hold the sand which helps close the 

 entrance. 



The finishing touches having been applied, Ammophila is usually 

 off and away immediately, though sometimes the fond mother seems 

 unable to sever her connection with the nest so recently made and 

 remains in the neighborhood visiting the nest occasionally to make 

 a few changes. Once I caught a wasp in a neighboring tree after 

 she had apparently finished her work; but she escaped through a 

 hole in the net. For the next hour she continued to come near 

 the nest again and again though she assiduously avoided me and 

 my net. Gradually, however, she seemed to forget her experience 

 and became so bold that I could approach close to her and easily 

 captured this artist of her race. 



Fig. 17 represents a section of the nests of wasps Nos. 72 and 

 73. It is a rare thing to observe two Ammopkilae digging their 

 nests so close together at the same time. Their behavior under 

 these conditions seems to me to justify a special description of them 

 here. 



