104 PROC. ENT. SOC. WASH., VOL. 23, NO. 5, MAY, 1921 



which the one at the extreme end was provided with three 

 grasshoppers and an egg in place and the other, being incomplete, 

 held only one grasshopper and no egg. 



It appears that the wasp does not deposit her egg until the 

 chamber has been completely provisioned. When this has been 

 done and the egg placed the chamber is at once sealed up. The 

 grasshoppers are placed upon their backs neatly arranged with 

 their heads all pointing towards the closed end of the burrow. 

 My limited observations on these two species indicate that the 

 egg is always placed on the first grasshopper brought into the 

 brood chamber but it is not deposited until the chamber has 

 been completely provisioned. In the case of T. dubia the egg is 

 placed on the sternum of the prothorax crosswise of the body 

 between the head and the prothoracic legs. Owing to the cir- 

 cumstances under which these observations were made it was 

 impossible to attempt any study of the development of the larva 

 of this species. 



Some idea of the activity of this species may be had from notes 

 on movements of the wasp that constructed the nest first opened. 

 She arrived at her nest with prey at 8:50 A. M. While she was 

 inside the nest I removed the long grass that almost concealed 

 the entrance to it. When the wasp came out at 8 :52 she seemed 

 confused by the change and spent the next five minutes buzzing 

 about the entrance and popping in and out of it. She finally 

 flew away at 8:57. She returned with prey at 9:20, left again at 

 9:21; returned at 9:45, left at 10:24; returned at 10:35, left at 

 10:36; returned at 11:00, left at 11 :35; returned at 11:43 and was 

 captured as she emerged at 1 1 :44. By comparing this record 

 with the number ot grasshoppers found in the brood chamber of 

 the first nest opened it will be seen that when the wasp remained 

 for a considerable time within the nest, thirty-nine minutes the 

 first time and thirty-five the second, this time was required for 

 depositing the egg, sealing up the brood chamber and enlarging 

 the tunnel for a new one. 



In approaching the nest with prey the wasp makes a loud 

 humming noise, poising in the air till the entrance of the nest is 

 located when she settles directly into the opening of it. I may 

 add here that in the case of the wasp that constructed the second 

 nest opened, I removed the grass from about the entrance to her 

 nest just as I had done with the first one, but this second wasp 

 did not pay the slightest attention to the altered conditions nor 

 did the change confuse her at all when she returned with prey. 



A nesting site of Tachytes breviventris Cress, was discovered in 

 a pasture on the grounds of the Catholic University of America, 

 Washington, D. C., in September, 1920. On an area probably 

 fifty feet in diameter eleven nests were counted while some dozen 

 more were widely scattered about. The soil of the nesting site 

 is sandy and at the level of the brood chambers it is almost 



