r 
MITES. 
43 
“ ‘ Editor, ‘ Farmer’s Gazette ’:—I have examined the Acari accom¬ 
panying your letter of 6th inst. There are more than one species of 
Mite among those sent, but far the greater bulk appears to be “ Tyro- 
glyphus longior ” (Robin and Fumoze); the others are in such small 
numbers that they may be neglected. T. longior is, as you evidently 
suspect, one of the Cheese Mites. The ordinary well-known Cheese 
Mite is Tyroglyphus siro, a species so like T. longior that it is difficult to 
distinguish the two. T. longior also lives in cheese, often in company 
with T. siro, and is frequently the more abundant of the two ; they do 
not, however, either of them, confine their attention to cheese. T. siro 
thrives and multiplies equally well on flour, linseed meal, &c., provided 
other conditions be favourable ; and, indeed, both species, and many 
of their allies, will attack an immense variety of dead and dried animal 
and vegetable substances; but they do not, as far as my experience 
goes, attack either in living condition, except that they appear some¬ 
times to eat small fungoid growths; neither do they, as a rule, like 
substances in a state of decomposition. T. longior will thrive only too 
well on dried cantharides, and causes great damage in parcels of that 
material. 
“ ‘ It is the characteristic of these two species, and some of their 
allies, that occasionally, when they find conditions thoroughly favour¬ 
able, they increase to such an enormous extent that the substance they 
are feeding on seems to be wholly composed of the Mites ; and a whole¬ 
sale druggist lately offered to send me as many pounds’ weight of the 
Mites as I chose to have. I should think that they were probably 
accidentally introduced into the hayrick (they are generally distributed), 
and that happening to find conditions of moderate warmth, slight 
damp, and appropriate food, which just suited them, they have 
increased to an extreme, but not altogether exceptional, extent. 
“ ‘ I do not see any reason why cattle should be injured by eating 
them. We, ourselves, are not injured by eating them, which we do in 
great numbers in cheese. Moreover, the fodder in warm stables and 
cow-sheds is generally pretty abundantly supplied with this and 
other allied species, but the horses and cows do not suffer from the 
circumstance, as far as we know. The only way in which it strikes me 
that they might be injurious is this,—that where minute creatures, 
like this, are in such immense abundance, as in the present instance, 
very large numbers are apt to get upon anything, whether living or 
dead, that is long amongst them; and although they are not in any 
way parasitic, yet the mere friction of such multitudes of minute 
claws, and of the fine hairs with which the creatures are so well 
supplied, often mechanically produces considerable irritation of the 
skin for a time; thus, porters engaged in unloading grain, and other 
things very much infested with allied creatures, have sometimes been 
