A) 
6 
seem to’ me to be decidedly on the increase. Hitherto, our studies 
of its life history have given us no hint of a method of control; 
but observations made during the spring of 1886 make it seem possi¬ 
ble that this destructive species may be added to the list of those 
capable of being held in check by the ordinary processes of an 
intelligent agriculture. The early period at which the presence 
of this insect may be detected in fields of the most various his¬ 
tory, has seemed to justify the inference that its occurrence has 
no close relation to the rotation practiced; but a long series of 
careful observations made very early , when the corn was but an 
inch or two high, failed to discover a single instance, out of a 
great number, in which this louse was present in fields where 
the ground had not been in corn the year preceding. It was seen, 
however, that the development of a winged generation may occur 
so soon as to give opportunity for very early infection of corn on 
stubble or sod.* 
The notorious soft maple bark louse ( Pul via aria innumera- 
bilis ), which so seriously injured soft maple trees in 1884, seemed 
to the casual observer, in spring of the following year, to threaten 
an equal injury; but upon close inspection late in June, the cottony 
egg masses of the female were found, in nearly every instance ex¬ 
amined, to harbor a coccinellid larva ( Hyperaspis ) by which the 
eggs were being rapidly devoured; and before the end of the sea¬ 
son the pest was reduced to insignificance throughout the greater 
part of the area infested by it. 
* Since tlie above was written, the winter history of this species has been determined, chiefly 
by investigations made, nndermy direction, by my assistant, Mr. C. M _W eed. J he eggs_are col- 
lected from the ground in autumn by the common brown ant, Ldtius etc ten vs. lhari.v m 
in spring’, before corn is planted, the young lice, as they hatch, are placed on the roots of pigeon 
gj-ass” (Spfaria), smartweed (J*olygo>>vT/i), and possibly some other weeds, and are reared there 
until the field is planted to corn—if this is done,-when they attack the corn roots or the sub 
terranean part of the stem. If the field is planted'to some other crop, the young lice matur e 
on the grass roots and produce a second brood, many of which acquire uings about the middle of 
May, and then disperse. Later, they seem to abandon the grasses entirely. 
