84 Annals Entomological Society of America [Vol.11, 



rotation (fig. lo) had been completed and the larva had decidedly 

 contracted. Fig. ii shows the situation of both Jarva and pupal 

 envelope at 12:20; fig. 12, at 12:22: fig. 13, at 12:27: fig. 14, at 

 12:32, and fig. 15, at 12:32?? p. m. At 12:35 P- ^i- there were ap- 

 parent on the body of the parasite larva small, roundish cells of 

 a yellow color. By this time the skin of the host had reached 

 the semiglobular, typical form, which did not materially change 

 afterward, though a slight movement in the larva could be 

 detected 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 living body of the host had been trans- 

 formed into a tough, dried, hardened protective covering the 

 cocoon of the parasite during its short pupal stage, by a process 

 of manipulation 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 oft' the leaves 

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

 ma}^ 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 indi- 

 cated in Plate i, fig. i, there are exceptions, 

 as shown by a case where, in a ^'ery young 

 Toxoptera, the position illustrated in text fig. 9 

 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 its w^ay out by way of a small disc which Fig. 9 - Unus- 

 it gnaws through both cocoon and skin and ^.f ^^Ll'^sfpflcbH's 

 pushes outward, as shown in fig. 10. Yet, tritici in body of 

 sometimes, the larva w^orks out of this case pre- num ^^'^^'^Enlar^ed 

 maturely, as shown in text fig. 11. This may, (original), 

 perhaps, be due to some mishaps in constructing 

 the anchorage previously mentioned. 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. 



* Note: Mr. Kelly has since found that the parasite slits the ventral skin 

 of the host, and, widening the rent spins a cocoon within the aphis skin and 

 anchors it fast where the slits are situated. 



