WASP STUDIES AFIELD 





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FIG. 59. The course of flight of Odynerus dorsalis to the puddle of 

 water. 



pellets, when she soared off to the northeast. We waited for 

 her at her old pond, and, although she had flown in the oppo- 

 site direction, she eventually appeared there, paused a mo- 

 ment for a load of water and hurried on back to her hole, 

 following her habitual route precisely, and arriving after 

 an absence of just 6 l /2 minutes. Why these roundabout 

 courses ? We do not know, but this shows that, even though 

 these wasps are familiar with the direct route, they do not 

 always adhere to it. The hole was now about two inches 

 deep; the pellets were larger and fewer to each mouthful of 

 water. Either the work was becoming more arduous or it 

 was telling on her strength, for she moved more heavily 

 and occasionally staggered when she dropped a ball. The 

 next three working periods were 8, 6 and 5 minutes, and in 

 them she took out only 8, 9 and 9 pellets. Our St. Louis 

 wasps generally worked at a different pace from Iseley's 

 Kansas O. dorsalis; the latter made the trip for water in less 

 than a minute, but with each load of water they removed 

 only 5 or 6 pellets of earth, while ours always took out from 

 7 to 15 pellets. 



In making her trip toward the northwest she now simpli- 

 fied her course somewhat to a more nearly direct route, 

 similar to the right-hand diagram in figure 59. Once more 



