2 BRITISH TYROGLYPHID^. 



make up for tlieir minuteness, and enable them to do 

 an amount of damage not generally realised, and which 

 would probably work out to rather surprising figures 

 were it possible to collect statistics on the subject. 

 The destruction which the ordinary cheese-mites, Tyro- 

 c/lypJms siro and T. longior, effect in cheese is a matter 

 of common knowledge ; but it is not so generally known 

 that the same species, and many allied Acari, are almost 

 equally abundant in, and injurious to, flour, hay, and 

 numerous other dried vegetable products. Samples 

 cut from hay-ricks have been sent me which, weight 

 for weight, must have contained as large a quantity of 

 the Acarus as of the hay ; and the whole of the rick 

 was in each case stated to be in the same condition, the 

 pieces sent being fair samples ; they came from first- 

 class farms. The stores of dried vegetable and even 

 animal drugs at wholesale druggists are very apt to 

 get into a similar condition unless great care and watch- 

 fulness is exercised. Cantharides often swarms with 

 Tyroglyphidse to an extraordinary degree, and is liable 

 to be destroyed by them ; so is ergot of rye, and, indeed, 

 most other drugs which consist of dried vegetable or 

 animal matter. Some species, of which Glycyphagus 

 domesticus is probably the principal, seem often to 

 establish themselves in such articles as rush-covered 

 chairs and tables, and to spread thence over the whole 

 house in immense numbers ; under these circumstances 

 they are sometimes wonderfully difficult to extirpate, 

 scarcely any amount of cleaning, white- wash ing, or 

 fumigation seems to be effectual. They probably in 

 these cases do not seriously damage the premises or 

 the hard wood of the furniture ; but their mere presence 

 in such large quantities, and being found running over 

 all domestic things, is a great annoyance to many, 

 indeed to most people. A fair example of what fre- 

 quently occurs in this respect is to be found in a 

 communication to ' Science Gossip,' 1880, p. 262, 

 which is as follows : " Would some reader kindly 

 give me some information regarding the best means of 



