5 
present in grain fields, as shown by its appearance every year, to war 
on these pests whenever the weather conditions make its breeding 
and multiplication possible, and its rate of breeding is so rapid (there 
being a generation about every ten days) that with a week or two of 
favorable weather it gains control over its host insects and destroys 
them. 
FOOD PLANTS. 
The spring grain-aphis is essentially a leaf-infesting insect, rarely 
being found on the stem. While preferring oats, it will readily attack 
wheat, rye, and barley, and may often be found on the underside of 
the lower leaves of corn. Corn excepted, its effect on the leaves of 
grain, when present in large numbers, is to cause the infested leaves 
to change to a red color, which seems to be very characteristic of 
Toxoptera and does not follow attacks of other species of aphides 
on these grains. The insect has also been found breeding upon a 
considerable number of grasses, any one of which may constitute its 
alternating food plant upon which it may survive the summer in 
different portions of the United States. It has been found breeding 
freely upon marsh foxtail (dAlopecurus geniculatus) in Oklahoma 
by Mr. W. J. Phillips, and by Mr. C. N. Ainslie in Kansas; on 
Agropyron occidentalis, also in Oklahoma, by Mr. Phillips, and by 
Mr. E. O. G. Kelly and Prof. C. P. Gillette in Colorado. Slender 
wheat-grass (Agropyron tenerum) was found moderately infested 
by Mr. Ainslie at Las Vegas, N. Mex. The species was found breed- 
ing upon Bromus at Washington, D. C., and also upon Porter’s chess 
(Bromus portert) at Las Vegas, N. Mex., and on an undetermined 
species of Bromus at Mesilla Park, N. Mex., all by Mr. Ainslie. 
The writer observed it very abundantly on orchard grass (Dactylis 
glomerata) in Indiana in 1890, and again excessively abundant in a 
small isolated meadow of this grass near Midlothian, Va., in April, 
1907. This meadow was located in a region not adapted to the grow- 
ing of grain, and there was no field of growing wheat or oats within 
5 miles. Mr. Kelly found it in Montana, inhabiting marsh spike- 
grass (Distichlis spicata) in such abundance as to be damaging this 
grass, which in that part of the country is known commonly as 
“salt grass.” It was found inhabiting slender wild rye (Llymus 
striatus) at Las Vegas, N. Mex., by Mr. Ainshe. Mr. Phillips found 
it attacking little barley (Hordeum pusillum) at Beloit, Kans., and 
Kingfisher, Okla., while the writer found this to be of frequent 
occurrence throughout Kansas. Mr. Kelly observed it abundant 
on squirrel-tail grass (Hordeum jubatum) in Montana, while Mr. 
Ainslie found it moderately abundant on /Zordeum cespitosum near 
Cimarron, N. Mex. Wherever Kentucky blue-grass (Poa pratensis) 
grows, the insect will probably be found breeding upon it through- 
[Cir. 93] 
