INFLUENCES AND EFFECTS. 219 



In the case of Isaria sphingum, which is the conidia form of a 

 species of Torrubia, 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 182G, Professor Sebert 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 caterpillars 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 posterior 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 affixed 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 muscce, or 

 Empusa rnmc<e in former times, which is now regarded as the 

 terrestrial condition of one of the Saprolegniei.% 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. 



Z " Wiegmann Arcliir." 1835, u. p. 354 ; " Ann. Nat. Hist." 1841, 405. 



