27 
Lge, but it is held that this could not be continued for any 
length of time without injury to the species, and eventually, 
bought, would result in its extermination. There are certain 
1 3 of plant lice, however, of which no males or oviparous 
t‘S have been seen. Such species are thought to produce males 
yg laying females locally or only at seasons which from some 
wn cause are especially favorable to this method of reproduc- 
ervations made by the writer during the past season indicate 
mbit for Aphis maidis. From the latter part of May when 
lant louse appeared on the corn till the middle of November 
the corn had long been dry and the ground had been many 
frozen, the corn louse was followed with special care; and 
'a hundreds of individuals were dissected under the micros- 
only wingless and winged viviparous females were seen during 
iason. About October 6th, most of the sorghum cane in Cen- 
[linois was ripe and ready for the mill. Aphis maidis had been 
l the season abundant on the blades and to save itself must 
depart. Upon examination the species was found to be repre- 
l mostly by pupae and alate females. The pupae, as was found 
j ufining them, were rapidly maturing and the winged adults 
^leaving the sorghum and scattering in all directions. While 
jjing at the edges of such fields at this time one’s person inter- 
i the flight of many of these winged lice. The roots were 
jearetfully searched for the root form, but it was not to be found 
tees where at the beginning of the season it was common. 
3 plants were searched with the glass for eggs, and, though 
of them had afforded nourishment to hundred of axdiides dur- 
le summer, no eggs could be found. The lice which were thus 
l to leave the sorghum field doubtless resorted to the corn, 
t was less advanced and for some time afterward continued to 
ih them appropriate food. 
;h the advance of the season the lice upon corn were also de- 
1 of food. But in this case the irregular development of the 
i which prevailed in most fields served to collect the lice into 
colonies by driving them gradually from their stalks to the 
er and less matured ones. At the last most of the lice were 
found between the outer husks of the greener ears and upon 
ed and immature stalks. These had not all collected there as 
id females, for the wingless louse showed itself capable of leav- 
stalk and finding a better one. Both wingless and winged 
es of of the aerial form were now isolated and confined: both 
found to give birth to living young. On the ninth of Novem- 
umerous specimens were collected in the fields and carried to 
ouse. Among them were many winged females, some pupae 
i few young. All proved to be viviparous. Some of them 
i alive November fifteenth; on the twentieth of this month the 
vinged female died with its body distended with matured em- 
(11 were counted.) The last to succumb was a pupa which 
some days later. 
e specimens seen in the fields November 9fch, were the last 
observed alive out of doors. Previous to this date there had 
J severe frosts, and the corn was nearly all dry and hard. The 
i 
