94 
THE PERIODICAL CICADA, 
loose soil lias to be gathered and pressed against the upper end of the 
cavity, which is accomplished by 'making the soil into little pellets by 
means particularly of the front femora and placing these pellets on the 
clypeal part of the head, carrying them upward and pressing them 
firmly against the top of the cavity. The stiff hairs that cover the 
head and border the inner sides of the fore tibia? and femora assist very 
materially in securing the earth while it is being transported. 
From time to time the burrowing insect rests and cleans the adhering 
earth from its forearms very much as a cat washes its face with its 
paws. The large, strong forelegs are moved over the roughened front 
of the head, the stiff hairs springing from the latter acting like a comb 
or brush to free the spines of adhering earth. 
DAMAGE OCCASIONED BY LARY.E AND PUP^E. 
During its underground life the Cicada has been charged with dam- 
aging, and even killing, fruit trees. At first thought this is not an 
unnatural inference when one remembers the immense numbers in 
which the insect often occurs. The most specific charge brought 
against them in this particular is the account published by Miss Mor- 
ris in 1S4G. 1 Miss Morris having suspected for a number of years that 
the failure of certain fruit trees over twenty years old was mainly due to 
the ravages of the larva? of the periodical Cicada, had an examination 
made of one of them, a pear tree that had been declining for a number 
of years without apparent cause. She says: 
Agreeably to my expectation I found the larva 1 of the Cicada in countless numbers 
clinging' to the roots of the tree, with their suckers piereing the bark and so deeply 
and firmly placed that they remained hanging for a half an hour after being removed 
from the earth. From a root a yard long and about an inch in diameter I gathered 
23 larv;e ; they were of various sizes, from a quarter of an inch to an inch in length. 
They were on all the roots that grew deeper than 6 iuches below the surface. 
The roots were unhealthy, and bore the appearance of external injury from small 
punctures. On removing the outer coat of bark this appearance increased, leaving 
no doubt as to the cause of the disease. 
In this particular instance there is some reason for believing that 
the damage to the tree had been caused by the larvae. The fact 
remains, however, that no damage has ever been detected in forests, 
where the Cicada emerges in countless myriads, the trees presenting 
as vigorous and robust a condition as in other districts where no Cicadas 
occur, and this is true also of old original trees and planted trees in 
parks or private grouuds. In orchards also where the insects have 
been so abundant that the ground was almost honeycombed after their 
emergence the trees themselves exhibited a good state of vigor and an 
inspection of the roots revealed no material injury save some small 
swellings or callosities with slight discoloration which might have 
resulted from the punctures. 
The underground development of the Cicada is so very slow, thirteen 
- 1 Proc. Acad. Xat. Sc. Phila., December, 1846 (1848), vol. 3, p. 133. 
