A WEEK WITH A MINING EUMENID. 169 



invariably followed the stinging. The capture of a caterpillar 

 usually caused considerable excitement on the part of the wasp. 

 Sometimes she would lose her footing and both insects would roll 

 from the leaf to the ground before the victim could be subdued." 

 Although I have watched this wasp searching the crumpled 

 leaves for caterpillars, I have never been on hand at the moment 

 she captured her prey. However, I have witnessed both the sting- 

 ing and the malaxation of the victim. The first time I noticed the 

 malaxation the wasp and the caterpillar were on the leaf of a weed 

 and the wasp was vigorously crushing the neck of the larva with 

 her jaws. Then the body of the caterpillar was moved forward 

 until every portion of the body had been crushed by the rapidly 

 moving mandibles. I witnessed the stinging on two occasions. 

 Once a wasp captured a paralyzed caterpillar which I had placed 

 on the ground near her nest. The larva was seized by the neck, 

 the abdomen of the wasp curved beneath the caterpillar, and the 

 sting of the wasp thrust into the thorax three times. On another 

 occasion, by means of forceps, I was attempting to pull a larva 

 away from a wasp. Suddenly she stung the caterpillar three or 

 four times. These thrusts were in the front part of the abdomen. 

 The stinging and the malaxation do not kill the caterpillars, but 

 leave them in a semi-paralyzed condition. In all of the nests that 

 I opened, if they contained eggs or young larvae, the caterpillars 

 squirmed when exposed to air. 



VISITORS TO THE COLONY. 



During my week's sojourn with these wasps several species of 

 insects visited the colony. A large species of assassin fly occasion- 

 ally visited the scene. She would rest quietly on the ground in the 

 midst of the colony and make her toilet. When a wasp approached 

 she would become as rigid as a stone ; but never did I see her make 

 an attempt to capture one of the wasps. 



TW T O species of dipterous parasites appeared. One fly (prob- 

 ably a species of Hilarclla 1 ) occasionally followed a laden wasp in 



i The scientific names of all the visitors are not given ; because, when they 

 were common, the experiments required so much of my time that I could not 

 capture them. On the afternoon that I set aside for capturing them no 

 visitors appeared. 



