THE CANADIAN ENTOMOLOGIST. 



239 



The Common Cheese Mite Tyroglyphus siro. — This tiny creature, 

 scarcely visible to the unaided eye, is soft, smooth and fleshy, with a 



whitish body and feet furnished with suckers 

 and claws. Figure 23, which represents one of 

 these mites highly magnified, will convey a 

 better idea of its general aspect than any ver- 

 bal description we can give. It lives in almost 

 every kind of cheese when a little decayed, 

 and particularly in the harder portions. When 

 in a warm atmosphere they are active, con- 

 stantly gnawing at the cheese and reducing it to 

 powder. This powder is composed of little 

 greyish balls of excrementitious matter, eggs, 

 both empty and unhatched, larvae, pupae, and 

 perfect mites, with cast skins and fragments of 

 cheese. Exposed to a low temperature, the 

 individuals soon gather into groups or heaps in hollow places in the 

 cheese, and there remain in a state of torpidity until awakened again by 

 warmth. '1 his mite is also found in flour. 



It multiplies very rapidly either in cheese or flour. A few specimens 

 transferred from a mitey cheese to an old cheese not mitey, will soon 

 colonize it thoroughly. They are probably harmless, since there are no 

 records of any disease occasioned by them, although they are daily 

 eaten in numbers too great to be estimated, and so carelessly, that hun- 

 dreds of living individuals must escape the grinding of the molars and be 

 swallowed alive. 



Fig. 23. 



WALSINGHAM'S PTEROPHORID^E OF CALIFORNIA 



AND OREGON. 



BY CHARLES FISH, OLD 'TOWN, MAINE. 



I desire to call the attention of Entomologists to a very valuable con- 

 tribution to Entomological literature recently made by Lord Walsingham. 

 The work is entitled Pterophoridce. of California and Oregon, and is pub- 

 lished in an octavo volume very neatly gotten up, and containing sixty-six 

 pages of letter press, fully illustrated by forty-eight colored figures on 



