XI 
favorable seasons of the two years just past, so that it now 
appears likely to clo considerable injury to the coming crop. 
The peculiarity of its recent history is the extension of its area 
of destruction northward, throughout the greater part of 
[Central Illinois. It has made, in fact, its first appearance for 
many years in a region where it is so little known as rarely to 
be recognized by the suffering farmers. A statement widely pub¬ 
lished by the daily press throughout the country in the summer 
of 1890, to the effect that the wheat of Illinois had been 
lattacked by a species of saw fly previously unknown, proved 
to be founded upon the presence of the Hessian fly, not recog¬ 
nized by those with whom the report originated. 
The American plum borer, (Plate II., Fig. 1, 3, and 5,) 
of whose discovery bare mention was made in my last Report 
(page IX), known then only from Sangamon county, is shown 
by our recent observations to occur also in Southern Illinois, 
as is shown elsewhere in my article on that species. 
The scale insect of the grape (Aspidiotus uvw), (Plate III., 
Fig. 1 and 2,) published hitherto only from Vevay, Indiana, 
and from Florida*, occurs abundantly in the vineyards of Pulaski 
county, and possibly elsewhere in the older grape-growing re¬ 
gions of the State. At Villa Ridge it seems to have done 
considerable damage and must evidently receive attention lest 
it become a wide-spread pest. 
A new corn root worm, Diabrotica V2^]mnctata, (Plate III., 
Fig. 3,) allied to the one now fairly well known to the agri¬ 
cultural public ( D . longicornis ), but differing materially in life 
history, was found locally very destructive to corn in Morgan 
county in 1889, and has since been shown to occur in smaller 
numbers as a corn insect in other parts of the State. 
The adult beetle from which this larva comes is a verv 
common insect, feeding most freely on plants of the squash 
family!, and much injury to corn hitherto unnoticed or 
misunderstood is very probably to be attributed to this 
root worm. The time at which the eggs are laid and the 
other particulars of its annual development make it impos¬ 
sible to check it by the simple expedient of rotation found 
completely effective for its ally. The first lot of specimens 
obtained from near Jacksonville, showed that it is subject to a 
bacterial disease, doubtless contagious, which turns the larva 
red,—a fact of some promise as respects this root worm, and 
of possibly still greater significance as an economic resource 
against the more destructive D. longicornis. 
*Rep. Ent. U. S. Dept. Agr., 1880, p. 310, and 2d Rep. Cornell Univ. Exper. Station 
(1882-83), p. 71. 
+ Also frequently on corn leaves. 
