DIPTKHOT'S KNKMIKS. 
1L>0 
1NSK( r r.vKAsri'Ks. 
As alroady notod, ainoii*^ tlic more o(lVc(iv(» natural onomios of the 
Cicada iwr tlic otluM* insects wliicli ])rcy npon llic ci^<j:s in tlic tw i<xs, on 
tlic n(n\ ly-liatclic(l larva\ and also, ])u( to a nuicli less (>.\lcn(, on the 
adults. The more coninion and cliai-actcristic of the insect enemies of 
the (liiferent stages of the ])eriodical Cicada arc given ])elow: 
l)ii'ii;i{()i s Enenhes. 
Some four species of two-winged llieshaN'c Ixhmi found to subsist as 
larva^ on tlu^ eggs of tlu^ Cicada, but none of these has been r(>ai-e(| 
to tluMidult stage and. therefore, their specific- identification is impos- 
sible. 
One of these bears some resemblance to an asilid, or, perhai)s, more 
remotc^ly, to a bombylid larva, and was found by Mr. K. AV. Allis at 
Adrian, Mich., feeding on the contents of 
the eggs of the Cicada, piercing the thin 
shells and extracting the juices. These 
larva^ are very minnte, not nmch exceeding 
a millimeter in length. 
The most interesting of the dipterous egg 
parasit-es is a cecidomyiid, which was found 
in February, 1886, with eggs deposited in 
sumac the previous season. AATien ex- 
amined, all the eggs had hatched except in 
some instances where they had been sealed 
up by the rapid growth of the wood, so as to 
prevent the escape of the larvae. One of the 
eggs thus inclosed was of an orange color, 
in distinction from the normal yellowdsh- 
white, and from it, on March 2, an orange- 
colored cecidomyiid larva emerged. Other larvie, apparently of the 
same species, were secured in May from eggs in alder twigs. From 
none of these, however, were adult flies obtained. The larva? ranged 
in length from 1 to l.o millimeters. Their general characteristics 
are uidicated in the accompanying illustration (fig. 52). 
The fly parasite of the adult C'cada seems to belong to th(^ family 
Tachinida^, which includes a number of species similarly attacking 
grasshoppers as well as many other insects. The larvae of these flies, 
which have not been carried to the adult stage, sometimes to the 
number of half-dozen or more, will occur together in tlie body of a 
Cicada, which they have almost or quite completely eaten out. 
•M 1 17— No. 71—07 y 
Fig. 52.— Cecidomyiid eyg parasite 
of the periodical Cicada: Larva, 
mucli enlarged, with anatomical 
details at side. vOriginal.) 
