isely: eumenid^ of kansas. 287 



average was twenty-two seconds. The two wasps worked 

 under the same conditions, as far as that is possible. Both 

 nests were in the same open space, being within three inches 

 of each other. They also had the same advantages of tempera- 

 ture, for I was watching both nests at the same time. The 

 second wasp began worl\ing ten minutes after the first one 

 had begun her second nest. Although the second wasp worked 

 more rapidly in digging, it took her twice as long to store six 

 caterpillars in her nest. 



Two other nests, whose progress I had kept note of from 

 their commencement until their completion, required a much 

 longer time for this process. One was closed twenty-one hours 

 after it had been begun ; the other was closed twenty-five 

 hours after its commencement. Both were nests with two cells. 



Two hesperid caterpillars were preyed upon by 0. dorsalis. 

 The larvfe of the spotted skipper (Pyrgus tesselata) was taken 

 by 0. dorsalis exclusively in Russell and Osborne counties; the 

 larvae of the black skipper (Philosara catidlus) was the only 

 caterpillar that I found in its burrows. The first caterpillar 

 was common on the poppy mellow (Callirhoe involucrata) , an 

 abundant and conspicuous plant in many lowland pastures. 

 I always found the larvae in a nest made of a crumpled leaf or 

 two, whose edges were held together by a silken web. Some- 

 times this web was in the heart of the plant. The black skip- 

 per larva Mr. Williams collected on the pigweed (Ama)/ranthiis 

 retroflexus) . 



One afternoon of the first week in August, at about 3 :20 

 o'clock, I stationed myself before a burrow to watch particu- 

 larly the storing of prey. In fifteen minutes the wasp visited 

 the burrow, but brought nothing. She left the nest quickly, 

 and in two and one-half minutes returned with a caterpillar. 

 Two minutes were required in storing it. She brought an- 

 other caterpillar in fifteen minutes, again staying in the nest 

 three minutes. The next caterpillar was brought in two and 

 one-half minutes. Shelhen spent twelve minutes in the field, 

 and returned with nothing. She brought a fourth caterpillar 

 in fifteen minutes and stored it in three minutes more. 



Evidently the cell was full, for when she came out Mrs. 

 Wasp flew in the direction of the river and returned in a 

 minute with her mouth parts glistening. She stayed in the 

 burrow two minutes, presumably to close the cell. Then she 



.1— Univ. Sci. Bull.. Vtl. VIII. No. 7. 



