. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. 348 THE MITES Demodex infection, but it is probable that sulphur applications in some form would reach and destroy them. Tongue-worms Related to the mites, but now placed in a distinct order, Lin- guatulina, are the tongue-worms. These animals have become so modified by parasitic life that the adults have lost nearly all re- semblance to the other members of their group, and have become so wormlike, both in form and life history, as to have been classified by older writers with the tapeworms (Fig. 146A)
. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. 348 THE MITES Demodex infection, but it is probable that sulphur applications in some form would reach and destroy them. Tongue-worms Related to the mites, but now placed in a distinct order, Lin- guatulina, are the tongue-worms. These animals have become so modified by parasitic life that the adults have lost nearly all re- semblance to the other members of their group, and have become so wormlike, both in form and life history, as to have been classified by older writers with the tapeworms (Fig. 146A). Only the larval stage gives a clue to their real relationships. Their long bodies are either flattened or cylindrical, and distinctly divided into rings or segments as in leeches. There is no dis- tinct demarcation between head, thorax and abdomen. On either side of the mouth are ot^Zocephaius a^if- t^o hooks which Can be retracted into grooves laius. X 3. (After like the claws of a cat (Fig. 145). These are Sambon.) usually looked upon as the vestiges of some of the appendages. At the bases of the retractile hooks there open a number of large glands, the secretion of which is believed to have blood-destroying power. The internal organization of the body is degenerate in the extreme; there is no blood, no respiratory system, no special sense organs, no organs of locomotion; little more than the barest necessities of racial existence — a simple nervous system, a digestive tract and a reproductive system. The sexes are separate. The adult worms live in the nostrils, trachse or lungs of car- nivorous reptiles and mammals, where they produce their myriads of eggs. The latter are voided with the catarrhal products of the respiratory system caused by the presence of the parasites. The egg-laden mucous excretions from the nose of an infected animal are dropped on vegetation and eaten by herbivorous ani- mals, whereupon the eggs (Fig. 146B) develop into larvae in the new host. Thes
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