INSECTS INJURIOUS TO MEATS 283 



a scarcity of food, for it has been shown that hypopi are 

 developed when food is present. 



It was formerly a source of wonder as to what became 

 of the hordes of mites when they had completely devoured 

 all of a given cheese, for example ; or how an apparently 

 clean storeroom became infested with these tiny creatures. 

 We now know that some of the partly grown mites, either 

 before or at the time the food disappears, transform to 

 hypopi and remain in a half comatose condition awaiting 

 events. As Howard says, "these fortunate survivors, 

 possessing their souls with patience, retire into their 

 shells and fast and wait, and as everything comes to him 

 who waits, some lucky day a mouse or house-fly or some 

 other insect comes that way, and the little mite clings 

 to it and is carried away to some spot — where another 

 cheese or food in some other form is at hand." It is 

 under these circumstances that the sucking disks to which 

 we have already referred perform their useful function, 

 namely, that of fastening the hypopus to its agent of 

 transportation, the mouse or the insect. This is un- 

 doubtedly the manner in which new food supplies and 

 clean storerooms often become infested. 



These mites are certainly widely distributed over this 

 country and indeed over the world. Considerable con- 

 fusion seems to exist, however, as to the identity of our 

 species with the European forms. It seems certain that 

 the common cheese mite (Tyroglypkus longior) and the 

 flour mite {Tyroglypkus (Aleurobius) farina) (Fig. 93) 

 both of which are European forms, occur here. 



These mites increase with great rapidity and in a short 

 time occur in enormous numbers. Flour, for example, 

 may become literally alive with these tiny creatures. A 



