78 



Annals Entomological Society of Ainerica [Vol. II, 



required for it to overcome a most serious outbreak of Toxoptera 

 and thus save from destruction vast areas of growing grain. The 

 species winters over in 

 the fields in the bodies 

 of its host. In many 

 cases this hibernation 



is passed as nearly or 

 quite fully developed 

 adults, ready to 

 emerge when the tem- 

 perature rises to the 

 neighborhood of 56° and continues for a sufficient length of time, 

 and where they have been prevented from emerging the pre- 

 vious fall, on account of the advent of cold weather. This is clearly 

 shown by the fact that Mr. E. O. G. Kelly found them in this 

 condition at Leavenworth, Kansas, on November 13. From a 

 lot of 50 parasitized Toxoptera that had been washed or rubbed off 



Fig. 5. — -Lysiphlebus depositing its eggs in the 

 body of a grain-aphis. Much enlarged (original.) 



Fig. C. — Lysiplilcbits tritici, principal parasite of the spring grain-aphis; 

 Adult female and antenna of male. Greatly enlarged (original). At right: Egg 

 of Lysiphlebus tritici. Highly magnified (original). 



the leaves of the young grain (fig. 7) and were taken out of the 

 mud about the wheat plants on February 28, after the winter was 

 practically over, Mr. Kelly found that of these 50 dead bodies, 

 17 contained full grown larv^ of the parasite, 12 contained pupae 

 of a light color and 2 1 contained pupae of a dark color, the latter 



