INFLUENCES AND EFFECTS. 219 
In the case of Isaria sphingum, which is the conidia form of a 
species of Zorrubia, the moth has been found standing on a leaf, 
as during life, with the fungus sprouting from its body. 
Other and less perfect forms of fungi also attack insects. 
During the summer of 1826, Professor Scbert collected a great 
many caterpillars of Arctia villica, for the purpose of watching 
their growth. These insects on arriving at their full size became 
quite soft, and then suddenly died. Soon after they became 
hard, and, if bent, would easily break into two pieces. Their 
bodies were covered with a beautiful shining white mould. 
If some of the catcrpillars affected with the parasitic mould 
were placed on the same tree with those apparently free from 
its attack, the latter soon exhibited signs that they also were 
attacked in the same manner, in consequence of coming into 
contact with each other.* 
During the spring of 1851, some twelve or twenty specimens 
were found from amongst myriads of Cicada septemdecim, which, 
though living, had the postevior third of the abdominal contents 
converted into a dry, powdery, ochreous-yellow compact mass 
of sporuloid bodies. The outer coverings of that portion of 
the insect were loose and easily detached, leaving the fungoid 
matter in the form of a cone aflixed by its base to the unaffected 
part of the abdomen of the insect. The fungus may commence, 
says Dr. Leidy, its attacks upon the larva, develop its mycelium, 
and produce a sporular mass within the active pupa, when many 
are probably destroyed; but should some be only affected so far 
as not to destroy the organs immediately essential to life, they 
might undergo their metamorphosis into the imago, in which 
case they would be affected in the manner previously described.t 
The common house-fly in autumn is very usually subject to 
the attacks of a mouldy fungus called Sporendonema musce, or 
Empusa musce in former times, which is now regarded as the 
terrestrial condition of oue of the Saprolegniei.t The flies 
become sluggish, and at last fix themselves to some object on 
* ‘Berlin Entom. Zeitung,” 1858, p. 178. 
+ ‘Smithsonian Contributions to Knowledge,” v. p. 53. 
t ‘ Wiegmann Archiv.” 1835, ii, p. 354; ‘¢ Ann. Nat. Hist.” 1841, 405. 
