282 HYPHOMYCETES. PART n. 



Melanconiei, which is more remarkable in regard to the 

 mode of fructification than any of the preceding Conio- 

 mycetes, for instead of successively assuming the form 

 and fructification of two genera, or two orders, the plants 

 successively assume the form and fructification of two 

 distinct families. 



The family of the HTPHOMTCETES takes its name from 

 its filamentous character. The mycelium gives rise to 

 white, dark brown, or bright coloured threads, simple or 

 compound, bearing naked spores on their extremities. Of 

 these there are five sub-orders and many genera. 



The sub- order Isariacei has four genera found on the 

 pupse of moths, on dead spiders, dead fungi, and dead 

 plants respectively. The group is characterized by 

 compound threads ending in pulverescent spores. Most 

 of the caterpillars of the Bombyx Rubi, or bramble 

 moth, fall victims to a species of Isaria, which has 

 several distinctly different periods and modes of fruc- 

 tification, and at last assumes the form of a very 

 beautiful fungus belonging to a different family. 



Near Paris, in the month of October, when the cater- 

 pillars of the bramble moth seek for shelter from the 

 cold, in the earth, or under long grass and withered 

 leaves, M. Tulasne and his brother found that most of 

 them were surrounded by tufts of a whitish down, which 

 increased so rapidly that it killed the caterpillars and 

 covered the whole of their body except the bristly hairs, 

 and assumed characters similar to the muscardine fun- 

 gus that kills the silkworm. This down is a mycelium 

 composed of extremely fine branched filaments felted 

 together, the upright fertile branches of which bear 

 whorls of branchlets each terminated by chaplets of 

 from ten to fifteen equal and spherical cells filled with 

 dust spores. These most minute spores germinated, and 

 put out filiform creeping germs which quickly emitted 



