456 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 12 



to its venter. The wasps were supplied with food by placing small 

 drops of diluted honey on a bit of leaf on the surface of the soil, before 

 covering the tins. When hungry the wasp came up, and though it 

 was dark in the tin, she licked up the nectar and straight way went 

 back to work. 



At first we only got an average of about one egg in two days from each 

 wasp; but after observing the activities of a specimen which I had 

 placed in a glass jar containing soil, I saw one of the difficulties. The 

 wasp spent hours mining, round and round the jar, dragging the para- 

 lyzed grub after her, evidently in an endeavor to get it deep enough 

 where the soil would remain moist, before forming a chamber and lay- 

 ing her egg. By supplying more moisture and examining the tins 

 several times a day, I found that it was an easy matter to get a wasp 

 to lay twice daily, and, in some cases as many as three eggs were pro- 

 duced in 24 hours. 



It is interesting to note that when I put several grubs in the tin, the 

 wasp straightway paralyzed them all, though she never laid on more 

 than one. This led me to the conclusion that two eggs per day was 

 perhaps her maximum average. 



Mr. Jarvis experimented with various methods of caring for the 

 grubs after they were parasitized, but none proved satisfactory for 

 breeding on a large scale. They all required too much handling. 



I, therefore, set to work to devise a plan, and began using boxes 

 similar to the ordinary greenhouse "flat," a number of which I made 

 up. These wooden trays are about 12 by 14 inches, inside measure- 

 ment, and three inches deep. Soil two inches deep was firmly pressed 

 into each of them and this was then indented with many oval cavities, 

 just the shape of the bottom of the normal cell which the wasp makes in 

 the soil, for the grub. I finally made a mold to form these depressions 

 in the soil very rapidly; and I was able to get exactly 60 of them for 

 each tray. See plate 19. 



As fast as the grubs were parasitized, they were placed in these 

 depressions on their backs and it was not necessary to handle them 

 again. By this method they were as well separated as if in their 

 original cells in the soil and they could not disturb one another; hence, 

 the larvse of the parasites developed very satisfactorily. However, 

 when they finished feeding, and tried to spin up their cocoons, I found 

 the same trouble that Mr. Jarvis had experienced when he kept the 

 parasitized grubs in the bottom of small jars — the larval wasps were 

 often unable to form the upper side of the cocoon, since the earthern 

 cells had no roofs to act as points of attachment. In the case of the 

 jars, I found that the cocoons were readily completed whenever I 



