1 88 WASP STUDIES AFIELD 



over the grassy part of the field, examining bare or rough- 

 ened spots just like the one described above. She moved 

 calmly and without haste or agitation. After examining 

 about ten spots in a couple of minutes, she arrived at a 

 certain inconspicuous pile of loose earth, in outward appear- 

 ance very similar to all the others. Instantly her manner 

 changed. She became greatly excited, nervous, quivering 

 with eagerness. She probed here and there in the pile until, 

 in a fraction of a minute, she had located the filled-up hole 

 beneath one side of the pile, and then eagerly began digging. 

 She burrowed steadily and rapidly in the freshly-stirred 

 earth, and pushed and flung the loose dirt out between her 

 legs and under her body. She worked with the furious 

 eagerness of a dog digging out a rabbit; surely, if she could 

 have barked or snorted, she would have done so. In a min- 

 ute or so she was through the plug of earth and disappeared 

 into the cell. We waited breathlessly, knowing that this 

 was the time when she was probably crushing the Priononyx 

 egg and laying her own but we nearly fell on our backs 

 when she came out at once, washed her face thoroughly, 

 rubbed her legs vigorously and unceremoniously flew away, 

 leaving .the hole wide open ! There was no indication of 

 her returning or giving any more attention to the place, 

 so we dug it up to see if it really was a Priononyx hole, and 

 if she had done anything. The case was quickly explained: 

 the hopper in the P. atratum chamber was reeking with 

 parasite larvae, but bore neither Priononyx nor Stilus egg. 

 Wise Stilus! The Diptera larvae had probably devoured 

 the Priononyx egg, and the Stizus knew at a glance that 

 the same fate would befall her babe if she left it there, so 

 she fled from the place at once. Where will adaptations and 

 interrelations cease! 



A few minutes later we noticed several parasitic Diptera 



