234 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



dant on a salt grass. The country was generally infested in the fall of 

 1908, and they successfully lived through that winter in the grain fields 

 in many sections, the worst infested wheat fields observed being those 

 following oats in northern Texas and southern Oklahoma, where in 

 early April of 1909 they had the appearance of a serious outbreak, but 

 the favorable weather in late April and May gave the crop advantage 

 and very little damage was done. A scattering few were observed in 

 North Carolina and South Carolina. 



In 1910 the species was very scarce west of the Mississippi river, but 

 was observed in damaging numbers at several places in Illinois and 

 Kentucky. In 1911 they were generally distributed through the east- 

 ern states. In eastern Oklahoma a limited incipient outbreak occurred ; 

 the heavy rains held it in check. They were reported from eastern and 

 southern New Mexico. In 1912 few were observed anywhere, as was 

 the case for 1913, except in South Carohna. In 1914 they appeared in 

 large numbers in South Carolina, Georgia, and in scattering numbers 

 over most of the eastern states, where they damaged oats and wheat. 

 They were quite common from northern Texas to Nebraska. In 1915 

 they were common in South Carohna, Tennessee, Georgia, Texas, 

 Oklahoma, Missouri, Arkansas, and Kansas. By November and 

 December they had become so numerous in Kansas and Oklahoma in 

 a few fields of wheat as to cause uneasiness among the farmers. In 

 1916 they occurred in damaging numbers in northern Oklahoma and 

 southern Kansas and in a small area in northeastern New Mexico, also 

 in scattering numbers to central Texas on the south and Nebraska on 

 the north. 



The Insect 



Toxoptera graminum is an aphid of pea-green color, with a distinctly 

 darker green stripe down its back, with black-tipped cornicles, and 

 with a single forked cubital vein — these characters readily distinguish 

 it from those most commonly found in wheat and oat fields, viz., Mae- 

 rosiphum granaria and Aphis avence. It takes its nourishment by 

 piercing the epidermis of the leaf with a beak adapted for drawing the 

 juices therefrom; the effect upon the leaf is to cause it to take on a red- 

 dish-brown color, and, when heavilj' infested, to die. 



In common with other aphids, its manner of reproduction is both 

 sexual and asexual. In latitudes south of the 35th parallel, it appears 

 that it onl}^ reproduces asexually, and north of this parallel both sex- 

 ually and asexually. One thing very noticeable in the outbreak at 

 Leavenworth was the entire absence of oviparous forms in the fall of 

 1907, and their presence in the fall of 1908. 



The minor outbreak of 1909 in southern Oklahoma and northern 

 Texas was not observed in the fall of 1908, nor was it followed in the 



