MITES, TICKS, AND OTHER ACARI. 507 



Linnseus described a mite under the name oiAcarus di/senteH(e, to 

 the presence of which was ascribed a persistent dysentery that attacked 

 one of his pupils, and some later authors have thought it may have 

 been the cheese-mite, or some of its allies ; but this is improbable. 

 Cheese-mites are constantly eaten in great quantities, and, so far as 

 can be judged, with perfect impunity; if they did cause mischief, 

 numerous cases would have been noted and reported, whereas there 

 are none recorded. A mite is also found in flour, sometimes in abun- 

 dance ; Hassell, however, says it is never present unless the flour is 

 damaged. Assuming it to be a separate and distinctive species, it 

 was described by Linnaeus and named A. farince, and has been so 

 figured and spoken of by naturalists down to the present time. But 

 Mr. Andrew Murray, whose excellent hand-book on " Economic Ento- 

 mology " is freely used in this article, asserts that the flour-mite and 

 the milk-mite are not distinct species, but are identical with the 

 cheese-mite. Not, he explains, that every species found on cheese or 

 flour is this species — for both are doubtless infested with others — but 

 that the old authors have made two or three species out of one. The 

 cheese-mite has been met Avith in very old linseed-meal, and has been 

 found on wounds that had been dressed with poultices made of lin- 

 seed-meal. Of course, its presence under such circumstances must be 

 mischievous. Another species which lives on cheese, T. longlor (Fig. 

 6), is distinguished from the above by its more rapid movements, 

 larger size, and longer and rounder body. Its habits and diet are 

 much the same, though they are not found, together. 



It is the species most commonly met with in stores of cantharides, 

 which are very subject to attacks of mites. This species, Mr. Murray 

 says, gave rise about 1837 to a good deal of talk among scientific 

 people, as having been supposed to be produced by electricity. There 

 was at that time in the semi-scientific world a vague idea in favor of 

 electricity being the source of many of the phenomena of life. The 

 limits and extent of its power were, of course, even less known than 

 at present, and all sorts of wild experiments were tried. One gentle- 

 man set up lines of electrical wires over portions of his estate, with a 

 view of ascertaining whether the plants would not thrive better under 

 what he supposed would be an increased flow of electricity. Others 

 made similar experiments in diflerent directions. One gentleman, Mr. 

 Cross, tried to produce organic beings by the aid of electrical appa- 

 i-atus. His process was to operate on volcanic stone kept moist by a 

 solution of silicate of potash and muriatic acid, constantly siabjected 

 to electricity. After carrying this on for some time, he was rewarded 

 by finding some of these mites wandering about his apparatus, and 

 arrived at the conclusion that they had been produced by his electrical 

 batteries. The species, therefore, enjoyed an ephemeral fame as a 

 human creation. It was sent to M. Turpin, in Paris ; having but a 

 single dead specimen to work from, he believed it to be a new species. 



