60 
attendants of the lice eagerly feed. The grass louse, on th 
other hand, is white m color, with a blackish head and othe 
blackish markings, but without any tint of green; and it hal 
no trace of cornicles, their place being taken by two minut 
openings in the corresponding segment of the body, each sur 
rounded by a delicate brownish rim. 
The evidences of serious injury by the corn root aphis are. ii 
short an unusual dwarfing and discoloration of the corn ai 
abundance of small brown ants in the field, nesting among th, 
s, and. finally, the presence of the bluish green insects them 
of the stalk ^ arger r °° tS ° f tbe Corn ’ es P ecia11 ^ near the basi 
The amount of injury may vary from a scarcely noticeabh 
check upon the growth of the plant to a total destruction o 
the corn over considerable patches, up to half an acre or more 
11ns more serious effect is, however, rarely, if ever, produced bt 
the loot louse alone Like most insect enemies,—especially thos« 
of suctorial habit, which abstract the sap of the plant they feed 
upon,—the corn root aphis serves to intensify the effect of drouth 
and other unfavorable influences, and it is often difficult, to say 
how much is to be ascribed to the action of the insect pest and 
iiow much to other causes cooperating'. 
There is some evidence to the effect that a too serious check 
to the growth of the corn results in the early evolution of a 
gieat number of Avinged plant lice of the second sprino- a-enera- 
tiom whose escape from the fields in which they start so breaks 
the foice of the attack that in a favorable season very badlv 
damaged plants may rally and make good corn; but if the in¬ 
sect injury is followed or reinforced by drouth, the corn may 
grow sluggishly the Avhole season through, and either fail to 
ear, or bear small imperfect nubbins only. Sometimes a field 
not mrested the year before is permanently damaged in June 
or e\en late m May, as the result of an early accidental con¬ 
centration of the Avinged lice originating in other fields. 
INJURY TO OTHER PLANTS. 
No other crop plants are especially liable to injury by this 
aphis, unless possibly we should except broom corn and sorghum 
Although not at all uncommon on these plants, it does not com¬ 
monly thrive on them, and so far as my observations liaArn ex- 
*? nd[ ’ e }Z h ° called injurious to them. It has been 
observed in the field, howeAmr, or bred in the insectarv, on the 
roots of a number of other species of plants, some of Avhich are, 
m tact, important to its maintenance. Many of the first o’ene- 
lation hatch from the egg in the field before the corn is readv 
to receive them, and at this time young smartAveed plants and 
oxtail grass (Polygonum and Setaria) are their principal re¬ 
source. these plants harden early and lose the succulence Avhich 
makes them especially desirable to plant lice, a fact which ac¬ 
counts in part no doubt for the early transfer of the lice to corn; 
