THE NATURAL ENEMIES. 95 
or seventeen years being occupied in attaining a size which with other 
species is achieved in as many days or weeks, that the very slow 
absorption of nutriment from the roots can scarcely have any effect 
on them, and the only injury, and this is very slight, is probably due to 
a poisoning of the roots, perhaps by tbe beak of the insect, as indicated 
by the slight discoloration of the cambium at the point of puncture. 
Callosities and other irregularities are, however, rare, and have never 
been observed by the writer. Very often also there are, undoubtedly, 
long periods of rest or dormancy, during which no food at all is taken. 
Referring to the injury noted by Miss Morris, it is a well-known fact 
that fruit trees have a natural term of life, and after twenty years 
they are very apt to show weakness and loss of vigor, and cease to be 
profitable. It is possible, therefore, that this is the true explanation 
of the condition of the trees noted by her rather than that it was due 
to the presence of the larva? of the Cicada. 
THE NATURAL ENEMIES OF THE CICADA. 
The fact that the periodical Cicada appears above ground so rarely 
prevents its having any peculiar or specific parasitic or natural enemies. 
We can not conceive of any parasite breeding solely either in the adult 
Cicada or in its eggs which could persist during the long period of 
years when no host was available. Equally remarkable also would be 
a parasitic insect the term of whose life should be so extended that it 
could live in the body of the Cicada larva during the years of its slow 
growth beneath the soil. Of the larger enemies of the Cicada, such as 
birds and mammals, the habit of feeding on the Cicada is necessarily 
acquired anew with each recurrence of a Cicada year. 
All these facts have a very potent influence in protecting the peri- 
odical Cicada, which as we have already pointed out, is particularly 
helpless, and were it not for these natural protective influences the very 
existence of the species would probably be early brought to an end. 
During their subterranean existence, the larva? and pupa 1 , when near 
the surface, are doubtless subject to the attacks of various predaceous 
Coleopterous larva', and many of them are unquestionably destroyed 
by this agency. Upon leaving the ground to transform they present 
an attractive food for many insectivorous animals, and the pupae and 
transforming adults are vigorously attacked by many different reptiles, 
quadrupeds, and birds, and by cannibal insects, such as ground beetles, 
dragon flies, soldier bugs, etc., while such domestic animals as hogs and 
poultry of all kinds greedily feast upon them. The preference shown 
by hogs running wild in woods for the Cicada is especially marked, 
and we have elsewhere commented on the fact of their rooting up the 
ground to get the pupa 1 in April and May, before the Cicadas have 
appeared at the surface of the ground for transformation. The birds 
are, perhaps, the most efficient destroyers of the Cicada, ami, as we 
have already noted, the English sparrow is particularly destructive to 
20110— No. 14 7 
