LARVAL SACRIFICE 387 



her rough red cohinins of elay stand for years as iiionunieiits 

 over the })irth heds of her offs])ring. 



The nest, a single cohinin of chiy two and a half to four 

 inches in length and close to three-quarters of an inch in 

 diameter, consists of a series of V-shaped layers placed side 

 hy side. The entrance to the nursery faces toward the 

 ground. Inside it is divided into several ten l)y twenty 

 millimeter cells, never exceeding four in numher, which 

 compared with the exterior, are quite smooth and polished. 



Here is an interesting fact: If the wasp has chosen her 

 original habitat among the stumps, she abandons it when 

 finished as an inconspicuous grey blotch that blends nicely 

 with its surroundings. In the forest she finds no red or 

 orange clay for building material. The swamps yield a rich 

 brown and the brook banks a shade of grey. The nest is of 

 necessity sombre in color. On the other hand, the nests 

 placed in the shutters of houses were all of rich, orange-red 

 clay, collected from a nearby excavation in the trail. They 

 were conspicuous objects to say the least, but the wasp 

 quickly covered her fresh paint with a neatly arranged layer 

 of termite's wings, cast off spider's skins and other bits of 

 refuse. At first I j)ut the occurence down as accidental, but 

 careful examination leads me to believe that it is a regular 

 habit of the wasp, in view of the fact that not a square milli- 

 meter of the underlying claj^ showed through the veil. \\^hen 

 the nests were finished they appeared old and disused. 



Each cell is usually provisioned with four wood roaches. 

 Upon the last one placed in the cell a single white egg, with 

 a yellow median line, is deposited. It is thrust under the fore 

 leg of the roach, where the leg joins the insect's body. It is 

 a tender spot where the young wasp, two days later, may 

 easily bury its head in the creature's flesh. The nmnber 

 of roaches in a cell varies according to their aggregate. Thus 

 a cell may contain two medium and one very large insect, 

 or six small ones, and while there is variation in the number 



