A WEEK WITH A MINING EUMENID. l6/ 



nests that had been marked. I shall transcribe both of those rec- 

 ords, because they have a direct bearing on this point. \Ye shall 

 call them records of wasp A and B. 



Record of wasp A: 



ii :2O A.M. The wasp places a caterpillar in the nest and de- 

 parts for the field. I place a small piece of tile near the opening. 



11:30 A.M. The wasp returns with a caterpillar. She does 

 not recognize the nest. She spends thirty minutes returning over 

 and over to the same spot, but fails to recognize the nest. 



12:12 P.M. / remove the piece of tile. Within two minutes 

 the caterpillar is carried into the nest. 



Record of wasp B: 



11:34 A.M. The wasp carries the caterpillar into the nest, 

 makes a flight of orientation, and then flies afield. / place a small 

 piece of coal to mark the nest. 



1 1 :44. The wasp returns with another caterpillar, goes to the 

 wrong hole, and, still bearing the caterpillar, flies about in irregular 

 curves. 



1 1 :45. The wasp starts into the hole, leaves it and tries another. 

 Still bearing the caterpillar, she flies about. 



ii :58. The wasp deposits the caterpillar in the nest and goes 

 for water. 



ii :59. The wasp returns and begins to scrape the rim of the 

 burrow and to add the material to the inside of the nest. 



Evidently the wasp when returning with a caterpillar is just as 

 sensitive to changes in her environment as she is when excavating. 



I have a very strong suspicion, but not positive proof, that these 

 wasps sometimes carry the caterpillar into the wrong nest. Occa- 

 sionally I have seen a wasp, belonging to some nest upon which I 

 had not experimented, remove a caterpillar and fly with it to the 

 field. The Raus ('18, p. 324) have noticed the same thing. They 

 write ('18, p. 324) : " From one hole we saw an 0. dorsalis emerg- 

 ing and watched her closely to ascertain her method of egress. 

 Imagine our surprise when we saw her carry out a P. catullits 

 caterpillar in her front and middle pair of legs, pause at the brink 

 of the hole for several seconds to adjust the caterpillar properly 

 between her forelegs and mandibles, and fly away with it." The 



