isely: eumenid^ of kansas. 263 



wasps had not hatched, and consequently the larder remained 

 untouched. Three of these cells contained eight caterpillars 

 each, one contained nine, and another ten. The nest un- 

 doubtedly at one time had contained at least fifteen or twenty 

 more caterpillars than it did at the time when I opened it. 



Why should the average number of caterpillars per cell have 

 been so much higher in Ness county than in Rush county? 

 There were two conditions that may have affected this differ- 

 ence. The caterpillar prey was much more abundant in Ness 

 county ; so were the wasps. A more important item is, that the 

 cells opened in Ness county which I could consider in this count 

 were stored on an average a week later than those that had 

 been in the same condition in Rush county, for any cell that 

 had been stored more than three days before we opened it was 

 likely to have its larder more or less depleted by the hungry 

 wasp grub. The weather had been considerably warmer while 

 we were in Ness county, and the activity of the wasps was cor- 

 respondingly increased. This may also have been one reason 

 for the larger number of cells in the nests in Ness county. 



I noted these wasps frequently on their hunting ground — 

 containing the food plants of their caterpillar prey. But in 

 spite of the comparative abundance of both the wasps and the 

 caterpillars, I saw the capturing of prey only twice. On one 

 occasion a wasp seized a caterpillar near the anal end, and by 

 repeated jerks pulled it from its hiding place between the disk 

 flowers in the gaillardia head. When the caterpillar finally 

 let go both rolled from the flower to a leaf below. For an 

 instant they were out of my sight. When I saw them again 

 the wasp was holding the caterpillar by the neck and was 

 stinging it under the thorax. I noted two thrusts. Then the 

 wasp quickly bestrode its prey and began maxalation. Some 

 movement of mine must have disturbed the wasp, for it 

 stopped suddenly, watched me for a moment, and then flew 

 away, leaving its victim on the leaf. The caterpillar appeared 

 to be dead, and did riot respond to any irritation. Unfortu- 

 nately I did not keep it to observe further developments. 



On another occasion I noted a wasp on a sunflower astride 

 a caterpillar and maxalating it. Then she turned the cater- 

 pillar ventral side up and continued chewing and twisting its 

 neck ; then she flew away with it. 



