AMMOPHILA AND HER CATERPILLARS 



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 entomologists as 

 Ammophila yarrowii Cres. They were so numerous that 

 one was distracted by their very multiplicity, but, by 

 singling out different individuals, we were enabled to verify 

 each detail of their operations. An insect, alighting, ran 

 about on the smooth, hard surface till it had found a suit- 

 able 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 neighbor- 

 ing 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 opening; 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 

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