OF WASHINGTON. 



113 



up to 4 p. m., after which the covering had become too opaque 

 to permit of further observations. Thus, within the space of 

 five hours the Hving body of the host had been transformed 

 into a tough, dried, hardened protective covering for the 

 parasite during its short pupal stage, by a process of manipu- 

 lation by the larva and a natural tanning process which renders 

 the skin of the dead Toxoptera so impervious to the weather 

 that these skins, so prepared, may be washed off the leaves 

 by beating storms, yet do not become easily disintegrated, and 

 may often be found in quantities on the ground underneath the 

 infested grain plants. 



While the normal position of the larva of the parasite in the 

 abdomen of the host is indicated in Plate VI, fig. i, there are 

 exceptions, as shown by a case where, in a very young Tox- 

 optera, the position illustrated in text figure 4 was assumed. 

 This, however, is unusual. Again, while the transformation 

 of Lysiphlebus from egg to adult takes place within the pupal 

 envelope, as previously described, and the adult makes it way 

 out by pushing out a small disc cut in the skin by the parasite 

 larva, yet sometimes the larva works out of this case prema- 



FiG. s- — o. Larva of Lysiphlebus tritici working its way prematurely from body 

 of Toxoptera graminum; b, same larva, somewhat further developed; c, same, still 

 more developed. (Drawings made for the Bureau of Entomology and published 

 by permission of the Secretary of Agriculture.) 



turely, as shown in text figure 5. Mr. C. N. Ainslie found 

 several of these prematurely issued larvse on the ground in 

 wheat fields in Kansas, under very seriously infested grain 

 plants where the Toxoptera were very much parasitized. 



