CHEESE MITES, ETC. 267 



CASE MM. Grenier and Aub^ devised an apparatus for exposing the 

 insects without removal to the vapours of such chemicals. It is 

 a large necrentome of tin, with fastenings, made with a trench to 

 be filled with water, so as to submerge the edge of the cover, and 

 is well adapted for museums and large collections, where the 

 labour of individual cleaning would be too great. But so far as 

 regards mites this is not necessary if the drawers or boxes only fit 

 moderately closely. Then it will be found sufficient to expose a 

 few chrystals of pure naphthaline for an hour or two in the drawers. 

 This is the simplest, easiest, and most effectual of all contrivances 

 to destroy mites. 



Where it is necessary to treat the insects in detail, another effec- 

 tive but more troublesome plan is to expose the infected insect to 

 the vapour of liquid ammonia — by placing a morsel of sponge in a 

 paint saucer and moistening it with a few drops of powerful liquid 

 ammonia. The insect is placed on a bit of cork alongside the 

 sponge, and the whole covered by a tumbler or small bell-glass, 

 so as to keep in the vapour j and in ten minutes or a quarter of 

 an hour the cure is generally complete. Sometimes it must be 

 repeated ; but this is rarely necessary. 



Insects should never be put away until they have been well 

 dried, and, if necessary, freed from fatty visceral matters. This 

 is particularly necessary for kinds brought up in captivity or full 

 of juice at the moment of their capture. 



No. 14 Tyroglyphus SIRO (JLinn., Latr.), (Acarus farinas, Linn.; A. lactis, Linn.\ 

 A. favorum, Herm. ; T. domesticus, Gerv., haud De G.). — 14. Mag- 

 nified figure of ditto. 



It is usual to hear the flour and the cheese mite spoken of by 



naturalists, described in books, and mounted by microscopists 



as two difi'erent and distinct species — but they are not so. It 



was Linnaeus who commenced the blunder by judging from the 



two different kinds of food, instead of from the mites themselves, 



and describing those which he found on cheese as the Cheese Mite 



(Acarus siro), those on flour as the flour mite (Acarus farinse), and 



