24 THE SOLITARY WASPS. 



many species of which thus breed in excavations made by them- 

 selves. 



While packing- specimens on an open space, uncovered by buffalo 

 grass, in the extreme vi^estem part of Kansas, the early part of last 

 July, the attention of a friend and myself was attracted by the numer- 

 ous wasps that were constantly alighting upon the ground. The hard, 

 smooth, baked surface sJiowed no indications of disturl^ance, and it 

 was not till we had attentively watched the insects that we learned what 

 they were doing. The wasp is a very slender one, more than an inch 

 in length, with a slender, pedicellate abdomen; it is known to ento- 

 mologists as ArrhmopMla Yarrowi Cres. They were so numerous that 

 one was distracted by their very multiplicity, but, by singling out dif- 

 ferent individuals, we were enabled to verifj- each detail of their opera- 

 tions. An insect, alighting, ran about on the smooth, hard surface till 

 it had found a suitable spot to begin its excavation, which was made 

 about a quarter of an inch in diameter, nearly vertical, and carried to 

 a depth of about four inches, as was shown by opening a number of 

 them. The earth, as removed, was formed into a rounded pellet and 

 carefully carried to the neighboring grass and dropped. For the first 

 half of an inch or so the hole was made of a slightly greater diameter. 

 When the excavation had been carried to the required depth, the wasp, 

 after a survey of the premises, flying away, soon returned with a large 

 pebble in its mandibles, which it carefully deposited within the open- 

 ing; then, standing over the entrance upon her four posterior feet, she 

 (I say she, for it was evident that they were all females) rapidly and 

 most amusingly scraped the dust with her two front feet, "hand over 

 hand," back beneath her, till she had filled the hole above the stone to 

 the top. The operation so far was remarkable enough, but the next 

 procedure was more so. When she had heaped up the dirt to her satis- 

 faction, she again flew away and immediately returned with a 

 smaller pebble, perhaps an eighth of an inch in diameter, and then 

 standing more nearly erect, with the front feet folded beneath her, she 

 pressed down the dust all over and about the opening, smoothing off 

 the surface, and accompanying the aetion with a peculiar rasping 

 sound. After all this was done, and she spent several minutes each 

 time in thus stamping the earth so that only a keen eye could detect 

 any abrasion of the surface, she laid aside the little pebble and flew 

 away to be gone some minutes. Soon, however, she comes back with 

 a heavy flight, scarcely able to sustain the soft green larva, as long as 

 herself, that she brings. The larva is laid upon the ground, a little to 

 one side, when, going to the spot where she had industriously labored, 

 by a few, rapid strokes she throws out the dust and withdraws the 

 stone cover, laying it aside. Next, the larva is dragged down the hole, 



