124 MITES AND TICKS. 



the middle. When fully grown it measures from a quarter to 

 half an inch in length. We have received it from Missouri, at 

 the hands of Mr. Riley, and Mr. J. A. McNiel has found it very 

 abundantly on horned cattle on the western coast of Nicaragua. 

 We now come to the genus Acarus (Tyrogly pirns), of which 

 the cheese and sugar mites are examples. Some species of 

 Acarian mites have been found in the lungs and blood-vessels, 

 and even the intestinal canal of certain vertebrates, while the 

 too familiar itch insect lurks under the skin of the hand and 

 other parts of the body of certain uncleanly human bipeds. 



Many people have been startled by statements in newspapers 

 and more authoritative sources, as to the immense numbers of 

 mites (Acarus sacchari, Fig. 148) found in unrefined or raw 

 sugar. Accordiug to Prof. Cameron, 

 of Dublin, as quoted in the "Journal of 

 the Franklin Institute," for November, 

 1868, "Dr. Hassel (who was the first to 

 notice their general occurrence in the 

 raw sugar sold at London) found them 

 in a living state in no fewer than sixty- 

 nine out of seventy-two samples. He 

 did not detect them in a single speci- 

 men of refined sugar. In an inferior 

 sample of raw sugar, examined in 

 148 Su"-ar Mite Dublin by Mr. Cameron, he reports 



finding five hundred mites in ten grains 



of sugar, so that in* a pound's weight occurred one hundred 

 thousand of these little creatures, which seem to have devoted 

 themselves with a martyr-like zeal to the adulteration of sugar. 

 They appear as white specks in the sugar. The disease known 

 as grocer's itch is, undoubtedly, due to the presence of this mite, 

 which, like its ally the Sarcoptes, works its way under the skin 

 of the hand, in this case, however, of cleanly persons. Mr. 

 Cameron states that "the kind of sugar which is both health- 

 ful and economical, is the dry, large-grained and light- colored 

 variety." 



Closely allied to the preceding, is the Cheese mite (Acarus 

 siro Linn.), which often abounds in newly made cheese. Lyonet 

 states that during summer this mite is viviparous. Acarus 

 farinse DeGeer, as its name indicates, is found in flour. Other 

 species have been known to occur in ulcers. 



