96 
THE PERIODICAL CICADA. 
them in and near cities, and, indeed, bids fair to completely exterminate 
them in such locations. 
In the perfect state they are attacked by at least one parasitic fly 
(TacJtina sp.) which lives internally in the body of its host. One of the 
large digger wasps, to be later described, also preys upon the adult, 
provisioning its larval galleries with the stung and dormant Cicadas. 
The Cicada is also attacked by a fungous disease, sometimes so abun- 
dantly as to ultimately destroy most of the male and many of the 
female insects. 
In the egg state, the Cicada has many very effective enemies, com- 
prising mainly parasitic flies belonging to the orders Hymenoptera 
and Diptera, and also various predaceous insects belonging to the 
orders Hemiptera, Keuroptera, and Coleoptera. A number of well- 
known predaceous mites, and other mites whose habits seem to be 
predaceous in this particular, are also found associated with the eggs 
of the Cicada under such circumstances as to leave little doubt of their 
feeding upon the eggs. All of these insect and mite enemies of the 
Cicada are more or less general feeders, and are simply attracted in 
numbers to the Cicada and especially to the eggs in the case of the 
egg parasites on account of the abundance of the food presented. In 
other words, we are furnished with a striking example merely of ready 
adaptation to new and favorable conditions. This is true also of the 
fuugous disease of the Cicada, which is probably normally present in 
other species of Cicada which are annual in appearance. 
INSECT PARASITES. 
As already noted, among the more effective natural enemies of the 
Cicada are the other insects which prey upon the eggs in the twigs, on 
the newly-hatched larva?, and also, but to a much less extent, on the 
adults. The more common and characteristic of the insect enemies of 
the different stages of the periodical Cicada are given below : 
DIPTEROUS ENEMIES. 
Some four species of two- winged flies have been found to subsist as 
larvae on the eggs of the Cicada, but none of these have been reared to 
the adult stage and, therefore, their specific identification is impos- 
sible. 
One of these bears some resemblance to an Asilid, or, perhaps, more 
remotely, to a Bombylid larva, and was found by Mr. E. W. Allis at 
Adrian, Mich., feeding on the contents of the eggs of the Cicada, 
piercing the thin shells and extracting the juices. These larvae are 
very minute, not much exceeding a millimeter in length. 
The most interesting of the dipterous egg parasites is a Cecidomyid, 
which was found in February, 1886, with eggs deposited in sumac the 
previous season. When examined all the eggs had hatched except in 
some instances where they had been sealed up by the rapid growth of 
