eG ees ve 
the young weeds sprouting so freely and abundantly in the moist earth, 
to a depth of four or five inches, that it seemed impossible to reduce the 
food supply of the lice to any considerable extent by mechanical methods. 
Our present knowledge of eifective economic procedure for the corn 
root aphis may be summarized in the form of the following recommen- 
dations: (1) that the fertility of the ground should be maintained as 
a general safeguard, and that cultivation should be so managed—espe- 
cially that.of the lower parts of the field—as to prevent so far as prac- 
ticable the seeding of pigeon-grass and smartweed among the corn; (2) 
that infested fields should be plowed deeply and thoroughly harrowed 
late in fall or during some suitable early winter interval; and (3) that 
a somewhat rapid rotation of crops should be systematically followed, 
corn usually being allowed to grow on the same ground but two years in 
succession. While some work remains to be done with reference to the 
precise value of these methods in practical application, there is no longer 
any doubt of their substantial usefulness, at least as a means of 
holding in check the injuries of the corn root aphis. 
DESCRIPTION OF CORN ROOT APHIS. 
Wingless Viviparous Female (Plate VIII., Fig. 1).—Body broad- 
oval. Head and prothorax blackish, remaining segments pale green, the 
first three with a transverse dusky mark at middle. Abdomen with 
blackish marginal patches on the second, third, and fourth segments, 
also numerous smaller spots of variable number and extent. The seventh 
and eighth segments have transverse blackish marks at middle. An- 
tenne dusky towards tip and slightly so at base. Cornicles black, cauda 
and anal plate dusky. Beneath nearly uniform pale green, except the 
usual oblong transverse chitinous plate on the seventh segment; beak 
black at base and tip; cox, most of femora, tips of tibis, and tarsi 
black. Antenne rather short, reaching fini to the hind coxe, I and 
II short and thick, both com pineal about two thirds as long as ITT. - 1V¢ 
V, and basal part of VI about equal, the latter about three fifths as long 
as the spur, IV and V combined about equal to IIT. Four outer joints 
imbricated throughout, more distinetly on the spur, a group of sensoria 
on VI at the base of its spur, and one near the tip of V, as usual, rarely 
also one near tip of IV or III. Beak passing middle cox, usually at- 
taining hind coxe. Lateral thoracic tubercles large and _ distinct, 
directed somewhat forward. Similar conical tubercles occur on the ab- 
domen, each surrounded by a dark ring; one on each side of the first 
segment, between the first two spiracles, and another pair on the seventh 
segment, each side of the chitinous plate. The cornicles are about as 
long as the third joint of the beak, rather slender and nearly cylindrical, 
often broad at base, the outlines straight or concave. The cauda is a 
little longer than its breadth at base, where it is widest, tapering to 
apex, which is broadly rounded. 
Length 1.4 mm., width .93 mm., antenne .57 mm., cornicles .10 
mm. The young are paler in color, and. have proportionally longer 
beaks and shorter cornicles. The chitinous space of the seventh seg- 
ment is almost wanting, and the cauda is shorter and broader, as in the 
pupa. . 
