FUNGI. 345 
by the voracious fungus. The dung-fly in certain 
districts has been almost annihilated by it. This 
disease has been long familiar to naturalists, but 
owing to the imperfection of their microscopes, its 
real nature was not ascertained until a compari- 
tively recent period. It was first accurately de- 
termined by De Geer about the end of last cen- 
tury; and a minute and graphic description is 
given of it by Goethe, who suffered nothing worthy 
of notice, however minute, to escape his observa- 
tion. This, and all other vegetable parasites at- 
tacking insects, seem to be one of the powerful 
and efficient checks provided by nature for re- 
straining within due limits the increase of crea- 
tures which, owing to their extraordinary fecun- 
dity, rapid development, and unbounded rapacity, 
would otherwise prove a terrible scourge. It is 
well known indeed that they help to prevent the 
destruction of forest-trees, which goes on to an 
enormous extent in North Germany through the 
ravages of caterpillars. 
The insect Spherias are found in different coun- 
tries. In Australia, where a gigantic species oc- 
curs on an enormous larva frequently found beside 
the banks of the Murrumbidgee, in North America, 
and in China, these deadly parasites are developed 
upon insects of different tribes. They form a 
favourite medicine in China, where a bundle of the 
