i26 THE PERIODICAL CICADA. 
especially on tlie end of the cavity, b}' means of its abdomen and 
middle and hind legs. If the direction of the larva, however, is down- 
ward, the loose soil has to be gathered and pressed against the upper 
end of the cavit}^ which is accomplished b}^ making the soil into little 
pellets by means particularly of the front femora and placing these 
pellets on the cl}^eal part of the head, carrying them upward and 
pressing them fii-mly against the top of the cavit}". The stiff haii-s 
that cover the head and border the inner side of the fore tibiae and 
femora assist very materially in securing the earth while it is ])eing 
transported. 
From time to time the l)urrowing insect rests and cleans the 
adhering earth from its forelegs veiy much as a cat washes its face 
with its paws. The large, strong forelegs are moved over the rough- 
ened front of the head, the stifT hairs springing from the latter acting 
like a comb or brush to free the spines of adhering earth. 
DAMAGE OCCASIONED BY LARV^ AND PUP^. 
During its underground life the Cicada has been charged Avith 
damamno-, and even killing, fruit trees. At first thouo:ht this is not 
an unnatural inference when one remembers the immense numbers in 
wliich the insect often occm's. The most specific charge brought 
against them in this particular is the account published by Miss 
Morris in 1846.^^ Miss Morris having suspected for a number of years 
that the failure of certain fruit trees over 20 jesiis old was mainly due 
to the ravages of the larvae of the periodical Cicada, had an examina- 
tion 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 larvae of the Cicada in countless numbers 
clinging to the roots of the tree, with their suckers piercing 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 larvse; they were of various sizes, from a quarter of an inch to an inch in length. 
They were on all the roots that gi-ew deeper than 6 inches below the sm'face. The 
roots were unhealthy, and bore the appearance of external injury from small 
punctm-es. 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 myiiads, 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 grounds. In orchards also where the insects 
have been so abundant that the ground was almost honeycombed after 
oProc. Acad. Nat. Sci. Phila., December, 1846 (1848), vol. 3, p. 133. 
