222 WASP STUDIES AFIELD 



but at 4 : 30 p. m. we examined the nest and were surprised 

 to find it just as we had left it. We removed the little lumps 

 of clay with which she had covered it, but the hoie was 

 empty, so we replaced them ; no prey after six and one-half 

 hours! We began to wonder if she had gotten lost in spite 

 of her accurate orientation. 



Early the next morning, we again examined the spot and 

 found it tightly filled in. A little careful digging soon re- 

 vealed the cut-worm, with the delicate egg on its side. 

 Hence she must have returned to the nest with the prey 

 some time between 4 : 30 and sunset, after an absence and 

 a search of six hours or more. Her locality study served the 

 purpose of her accurate return, although many marks were 

 required to guide our return. 



In another case, the burrow was ready for use and the 

 wasp proceeded to close it temporarily, as described else- 

 where, while she went foraging. Here her judgment must 

 somehow have been amiss, for the first two pellets which she 

 brought were so small that they fell down into the hole ; but 

 the third was large enough to rest on top nicely like a lid. 

 Then she concealed the spot deftly by adding some other 

 bits of earth and a kick or two of dust, and departed for 

 green fields. She did not take the usual flight of orienta- 

 tion, but began by searching in the weeds nearby. She 

 flitted or hopped from plant to plant, but while doing this 

 her path described a circle around the hole. Suddenly she 

 flew directly away out of our sight. Five minutes later, she 

 returned and continued scanning the weeds in this region, 

 and at one time even walked over her own nest and stopped 

 short on her pile of pellets for a moment, then flew away. 



In observing pictipennis, the fact is demonstrated again and 

 again, that the insects, when returning to the object of their 

 search, are not guided by any special sense, but in all prob- 

 ability, as the Peckhams, Turner and others have shown for 



