152 THE SOLITARY WASPS. 



■witli it backward for a long distance — as mucli as four or five 

 feet. This recalls the wasp which is said to fly backward before 

 a moving horse and catch the flies that are hovering over it . 



P. marginatus is not troubled by any notion as to the family 

 connections of the spider that she takes. Anything will do 

 provided she is strong enough to overcome it and carry it to her 

 nest. The effect of her sting is quite variable since in some 

 cases the victim was killed at once while in others it was but 

 little affected in the beginning and lived for eighteen or twenty 

 days. 



Although we have made observations upon thirteen individ- 

 uals of this species we have never succeeded in getting the spi- 

 der with the egg upon it. 



Pmnpilus interruptus Say. 



Early in the afternoon of the fifth of July, we saw this small, 

 yellow-banded wasp, flying slowly about from leaf to leaf and 

 from plant to plant, dropping to the gi'ound, now and then, to 

 run a little distance on the tips of her toes, in a peculiarly dainty 

 manner as though the ground were not good enough for her to 

 walk upon. She came back, again and again, to a spot under 

 a weed where there was a round shallow hole in the ground, 

 and presently she began, to work at this, showing that it was a 

 partly made nest. She carried the earth out in her mandibles 

 depositing it at the edge of the hole, and, after a little, pushed 

 away the accumulation with her feet. As she went deeper 

 the dirt was passed under her body and pushed up to the sur- 

 face with her legs. There was no kicking and all her motions 

 were slow. Every few minutes she flew up to a twig where 

 she stood very high on her legs, holding her wings up stiffly 

 at a right angle to her body. This manner of lifting the wings 

 was very peculiar, and gave her somewhat the look of the wasps 

 of the genus Yespa. When she had gone her own length into 

 the ground she came out and looked at her prey, a large Epeira 

 striw, which was hanging in the crotch of a weed close by. 

 After this she flew off toward the west and was gone five min- 



