. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. 388 LICE dt\,m. M^. npj ttplj General Structure.— Lice are small wingless insects constituting the order Anoplura. They were formerly classified as a suborder of the Hemiptera or true bugs, but recent studies have shown the erroneousness of this grouping. The mouthparts are adapted for piercing and sucking. The piercing apparatus (Fig. 171B) consists of four needle-like organs, one of which is the deli- cate salivary duct, which can be withdrawn into Fig. 171. Mouthparts of a body louse;
. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. 388 LICE dt\,m. M^. npj ttplj General Structure.— Lice are small wingless insects constituting the order Anoplura. They were formerly classified as a suborder of the Hemiptera or true bugs, but recent studies have shown the erroneousness of this grouping. The mouthparts are adapted for piercing and sucking. The piercing apparatus (Fig. 171B) consists of four needle-like organs, one of which is the deli- cate salivary duct, which can be withdrawn into Fig. 171. Mouthparts of a body louse; A, longitudinal section through head; B, mouthparts from sac under pharynx and oesophagus; buc. t., buccal tube; m., mouth cavity; ph., pharynx; oes., oesophagus; retr. sac, retractile sack for mouth- parts; prot. m., protractor muscles of pharynx; ret. m., retractor; dil. m., dilators; d. p., dorsal g^ JJ^^Jg pouch under the piercer; sal. d., salivary duct; V. p., ventral piercer; V. pi., ventral plate = labium (?). (Adaptedfrom pharynx (Fig. 171 A). Harrison.) This type of mouthparts readily distinguishes the true lice from the bird lice, which constitute the order Mallophaga (Fig. 172). In the latter there are nipper - like mandibles fitted for bit- ing instead of sucking, and these parasites feed only on hair, feathers, etc., and not at all on blood. In other respects the sucking Hce and bird Hce show a considerable. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Chandler, Asa Crawford, 1891-. New York, J. Wiley
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