67 
^ssivelv abundant. Colonies started in old corn fields which 
e/ 
ave been planted to some other crop thus abandon them, after 
ving for a time on smart weed, pigeon grass, and the like, and 
?sort to the growing corn; but in midsummer the roots of 
lany other plants become infested—purslane, Panicum (tickle 
rass), pigeon grass, and possibly squash, although our at- 
mipts to breed root lice from this last plant on corn were 
uite unsuccessful. 
Even ragweed will support these lice at least temporarily, as 
e proved in 1889 by transferring half-grown young of the sec- 
nd generation from smart weed roots to ragweed, where they 
ved and fed until they acquired wings, five days later. In 
utumn we have found the last viviparous generation and the 
viparous female generation following, on purslane, dock (Rumex 
rispa), fleabane (Erigeron canadense), black mustard, sorrel 
Oxalis stricta), and the common plantain (Plantago major), 
ot to mention two other plants not recognized or determined 
t the time. 
The bisexual generation of root lice makes its appearance in 
3rn fields as early as October 1, and continues there throughout 
tie month, pairing and depositing eggs. Our only observation 
f the sexes in copula was dated October 21. We have not 
>und the oviparous female anywhere in the earth except in the 
urrows of ants, and there, doubtless, the eggs are laid. Cer- 
rinlv they are collected at that season in the chambers of the 
K. 
nts' nests, and carried through the winter there as already 
escribed. 
The ants, in the meantime, have continue! their development 
i their small and scattered colonies, the larvae beginning to 
upate by the middle of May and the sexes emerging early in 
ugust. Just when and where the eggs are laid by the ferti- 
zed female we have not yet determined; but specimens of this 
?x have been found in the earth, alive, as late as November 1, 
nd the continual appearance of young larvae in the home nests 
ntil the middle of the following summer shows that eggs are 
lid, apparently by workers, at frequent intervals through the 
arly part of the season. 
The life history of the aerial corn louse, including its relation 
3 the root form, has proven a particularly refractory subject, 
nd is not yet complete. The connection of this form and the 
3ot louse as different stages of the same species was assumed 
ithout proof by the early observers, and has not yet been ex- 
erimentally demonstrated; but, on the contrary, a great nuin- 
er of attempts at demonstration have almost completely 
died. The leaf louse has never been certainly brought out of 
he root form, nor has the root louse been bred from the aerial 
)rm, and the evidence of a connection between the two is in- 
irect and circumstantial; while the proverbial difficulty of 
roving a negative, and the fact that the annual origin of the 
erial louse and the method of its hibernation are both un- 
nown, make a present conclusion unwarranted. 
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mam 
