CHEESE MITESy ETC. 261 



CASE or at all events actively aided by, two parasites, an Anguillula and 

 a Tyroglyphus, which are remarkable for their prodigious fecundity 



XIV. 



Tyrogflyphus rostro-serratus, under-side. Copied Ditto, side view. Copied from Megnin's figure, 



from Megnin's figure. About size of cheese-mite. 



when they find themselves in conditions favourable for their 

 development. The proof that these creatures are the very active 

 although indirect agents of this putrid decomposition, is that 

 mushrooms on which they have been placed are, in less than 

 forty-eight hours, reduced to a state of black and deliquescent 

 putrescence, on which myriads of these animalcules swarm ; while 

 other mushrooms in the identically same condition, which have 

 not been subjected to that inoculation, and which have been iso- 

 lated from the spoiled mushrooms, dry up or become mouldy, and 

 take from eight days to a fortnight to decompose spontaneously. 



The Tyroglyphus rostro-serratus is a sociable Acarid. It is 

 always, in great troops, in which all the ages are represented, that 

 it lives on the mushrooms in course of decomposition. It has a 

 life in some sort amphibian; for from the moment when the mush- 

 room begins to decay, to take a brown colour and become humid, 

 it is in the stratum of liquid half a millimetre in depth which 

 covers the surface of the fungus that the Tyroglyphi in question 

 move about completely bathed in this liquid, and in the midst of 



