47 
reaching beyond the base of the forelegs. Wings erect in repose, of 
usual form, third discoidal vein twice forked, transparent; veins 
slender, slightly dusky, the stigma elongate fusiform and rather 
slender; the subcostal vein for some distance from the base recedes 
somewhat from the costal, and then at about two-thirds the dis- 
tance approaches the costa; the first vein about three times as far 
from the second at the tip as it is at the base; the second is 
slightly farther from the base of the third than the base of the first. 
The second fork arises near the apex of the wing; the stigmatic 
vein curves somewhat sharply at the base, and then is nearly 
straight to the tip.” 
The head and body are 1.2 mm. long by .57 mm. wide. The 
antenne measure .85 mm.; the third joint is a trifle longer than 
the fourth and fifth together, and the sixth considerably exceeds the 
third in length, its filament being about twice as long as the basal 
part. Wing 2.4 .mm.; honey-tubes .12 mm., tail one-half 
that length. 
Pupa. (Plate IV, Fig. 2). The body is 1.5 by .86 mm.; antenne 
.63 rmm., the relative length of the joints as in the winged female. 
aigtews female. (Plate IV, Fig.1). Body 1.43 mm. by .85 mm.; 
honey-tubes .14 mm., antenne ./ mm. long, the relative length 
of the articulations about the same as in the winged female. 
The color is pale green, with the head and_ transverse 
bands of the thorax dusky. The antenne, beak, legs, honey- 
tubes, tail, and tip of the abdomen are black, as are also 
several rows and dashes on the back of the abdomen, quadrate 
blotches on the sides and under surface of the thorax, and a patch 
about the base of the rostrum. The eyes are red.. The body of a 
full-grown individual measures 1.4 mm. by .93 mm. The antenne 
are about .6 mm. long, the fifth joint about equal to the basal part 
of the sixth, the fourth a trifle shorter, the third and the filament 
of the sixth of equal Jeneth, each a trifle longer than the fourth 
and fifth taken together. The rostrum is very long, attaining the 
abdomen. 
LIFE HISTORY. 
I am not at present prepared to give in full the life history of 
the corn plant-louse, not having yet complete proof of the exact 
connection between the root and aérial forms, or of the place and 
mode of hibernation. I will, therefore, content myself with giving 
at this time the dates and stages under which we have actually 
collected the species in Illinois. 
It first makes its appearance upon corn under ground, late in May 
and early in June, attacking not only the roots, but likewise the 
sprouting stem beneath the surface. The wingless root form has 
been collected here by us on the 22d of May, and at several dates 
in June from the 1st to the 30th. It continues abundant, in this 
stage, on corn roots throughout the month of July, and was also 
obtained by me upon sorghum roots in smaller numbers on the 25th 
and 31st of that month. It so happened that we made no search 
for the root-louse in August, but it was found early in September, 
and also upon the 8th of October, the latest date at which we were 
