PROC. ENT. SOC. WASH., VOL. 23, NO. 5, M \V, \'>2\ 105 



wholly pure fine sand. The burrows were approximately three- 

 eighths of an inch in diameter and extended downward vertically 

 to a depth of from nineteen to twenty-tour inches. From the 

 bottom of the vertical tunnel lateral tunnels from four to eight 

 inches in length were constructed at right angles to the vertical 

 shaft and in radiate arrangement. In some cases the radiating 

 laterals were at two levels one about four inches above the other. 

 A brood chamber is constructed at the end of each lateral and 

 when provisioned the lateral between the brood chamber and 

 the main shaft is filled up with sand. I found no evidence of 

 two or more brood chambers in any single lateral. 



This species like the preceding species carries its prey to the 

 nest in flight and like it makes a loud humming noise as it flies. 

 The weight these wasps carry in flight is astonishing. Two 

 wasps and their victims were weighed immediately after capture. 

 One 'wasp weighed 160 mg and her prey 200 mg, the prey being 

 in this case 1.25 times as heavy as the wasp; the other wasp 

 weighed only 130 mg but her prey weighed 230 mg, the prey 

 being in this case 1.77 times as heavy as the wasp that carried it. 

 The first wasp carried her prey with little difficulty but the 

 second found her task laborious. In searching for the entrance 

 to her nest this second wasp was compelled to alight several 

 times to rest, and the rapidity and violence of her respiratory 

 movements plainly showed how great were the exertions 

 required to enable her to carry her heavy load. 



The entrance to the nest is always left open and when the 

 wasp returns with prey she endeavors to alight in the opening, 

 which, on the nesting site under observation, was a conspicuous 

 . hole in a pile of light sand. Consequently when she approaches 

 her nest with her heavy load she circles about in the air or poises 

 on the wing at about the height of a man's head until she locates 

 the opening of the nest when she drops down directly into it. 

 Frequently, perhaps because of fatigue, on coming down she 

 lands a few inches to one side of the entrance. In such cases she 

 invariably rises on the wing with her load, circles about and 

 tries for the entrance again. I saw this performance repeated 

 by one wasp no fewer than four times before she succeeded in 

 landing in the entrance to her nest. I observed one wasp do 

 this when she had missed the entrance less than two inches and 

 with no obstacle whatever between her and the opening of the 

 burrow. 



In the brood chamber the grasshoppers are neatly arranged 

 upon their backs lengthwise of the chamber with their heads 

 pointing towards its outer end. The number of grasshoppers 

 found in the different chambers varies from one to four. The 

 usual number was four but I found in two instances a developing 

 larva in a brood chamber that had been provisioned with only 

 one grasshopper. This means that the mother wasp provides a 



