. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. 340 THE MITES the body is hard and chitinous, there is no mouth or mouthparts, the legs are short and stumpy, and there is usually a raised area on the ventral surface with a number of tiny sucking discs. By means of these suckers the hypopus attaches itself to insects or other creatures and is thus transported to new localities, the entire object of the hypopus stage apparently being to secure passage to new breeding grounds. After dropping from its unwilling transporter the hypopus moults into an eigh
. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. 340 THE MITES the body is hard and chitinous, there is no mouth or mouthparts, the legs are short and stumpy, and there is usually a raised area on the ventral surface with a number of tiny sucking discs. By means of these suckers the hypopus attaches itself to insects or other creatures and is thus transported to new localities, the entire object of the hypopus stage apparently being to secure passage to new breeding grounds. After dropping from its unwilling transporter the hypopus moults into an eight-legged nymph again, which, after feeding, develops into an adult. The Tyroglyphidae are all quite similar Fig. 141. Hypopus or jn appearance, and the characters which traveling stage of 1 yro- . giyphus, ventral view, separate the species, and even the genera, Much enlarged. (After are few and minute. A considerable num- Banks.) ber of species may attack persons who handle infested materials, and they are the cause of " grocers' ; This affliction is caused especially by various species of Glyciphagus and Tyroglyphus. Of historical interest is a case of dysentery apparently due to a Tyroglyphus, T. longior, (Fig. 140) which occurred in one of Linnaeus' students. The mites were abundant in his faeces, and were found to live and multiply in a juniper-wood cup which he used. As shown by Castellani, an itching rash known as " copra itch," occurring among the laborers in the copra mills of Ceylon where cocoanut is ground up for export, is caused by a variety of this mite, called T. longior castellanii. Copra itch occurs also among stevedores who handle copra in London. Another species, Glyciphagus buski, was taken from beneath the skin on the sole of the foot of a negro in England; it had caused large sores. The negro attributed the affliction to the wearing of a pair of shoes loaned him by a similarly affected negro from Sierra Leone, Africa. Another speci
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmedical, bookyear1918
