THE FOOD OF THE LARVA AND PUPA. 123 
Perhaps the first writer to pomt out and demonstrate the true 
method of feeding of the larva and pupa of this insect in their under- 
eround existence was Miss Morris, of Germantown, Pa. That the 
Cicada larve and pupz pierce small roots with their sucking beaks 
and feed on the juices of the plant, as do other plant-feeding hemip- 
terous insects, as their normal, if not their sole method of subsisting 
was fully proved by her investigation, and has been confirmed repeat- 
edly in the diggings made by the writer, and there can no longer be 
any possibility of doubt in the matter. Jn practically every case, in 
the writer’s experience, where the cell in which the larva rested was 
taken out in condition for examination a small root, one-sixteenth to 
three-sixteenths inch in diameter, was found to border usually the 
upper end of the cell, and in several instances larve were found with 
their beaks so securely embedded in the root that they were not easily 
loosened. In other instances the roots showed, by the slight swell- 
ing and reddish discoloration beneath the bark, unmistakable signs of 
having been punctured. 
The root-feeding habit can be best witnessed in light, rich soils, and 
in the plantings of the brood of 1889 under oak trees on the Depart- 
ment grounds the soil beneath these trees was so thickly inhabited 
that between the depths of 6 and 12 inches every spadeful of earth 
would throw out numbers of the larvee, and a most excellent opportu- 
nity was afforded for the study of their habits. In hard, packed 
soils, perhaps scantily supplied with roots, the difficulty of getting out 
the cells in perfect condition is such that one might easily be led into 
error, and the comparative rarity of the larvee in such soils adds fur- 
ther to the difficulty of determining their feeding habits. 
It is for this reason, I have no doubt, that the opinion has obtained 
in some quarters that the larve subsist not on the roots of plants, but 
on the nourishment obtained from the surface moisture of the roots, 
or the general moisture of the earth, which might be supposed to 
contain more or less nutrient material arising from the decomposition 
of the vegetable matter. That the moisture of the surrounding soil 
may, and doubtless does, supply the very delicate, thin-skinned larvee 
and pupe with a certain amount of liquid by absorption through the 
skin may be admitted, and in fact when the darve are taken from 
their natural surroundings and exposed to the air they very rapidly 
dry and shrivel. Larve are doubtless occasionally found in cells 
away from roots, and this may be explained by the fact of their being 
at that time either undergoing one of their long resting or hibernating 
periods, which may be of frequent occurrence in such an extremely 
long-lived species, or. they may be burrowing in search of roots on 
which to subsist. 
