. Handbook of medical entomology. Insect pests; Insects as carriers of disease; Medical parasitology. Pediculus Corporis 8S The adtdt stage is reached on the eleventh day, after three molts, about fotir days apart. Adults enter into copulation about the fifth day and as the eggs require eight days for development, the total cycle, under favorable conditions, is about twenty- foiu- days. Warburton's data differ considerably from those com- monly quoted and serve to emphasize the necessity for detailed studies of some of the commonest of parasitic insects. Body lice are voracious feeders, produc
. Handbook of medical entomology. Insect pests; Insects as carriers of disease; Medical parasitology. Pediculus Corporis 8S The adtdt stage is reached on the eleventh day, after three molts, about fotir days apart. Adults enter into copulation about the fifth day and as the eggs require eight days for development, the total cycle, under favorable conditions, is about twenty- foiu- days. Warburton's data differ considerably from those com- monly quoted and serve to emphasize the necessity for detailed studies of some of the commonest of parasitic insects. Body lice are voracious feeders, producing by their bites and the irritating saliva which they inject, rosy elevations and papules which become covered with a brownish crust. The intense itching pro- vokes scratching, and character- istic white scars (fig. 67) sur- rounded by brownish pigment (fig. 68) are formed. The skin may become thickened and take on a bronze tinge. This mela- noderma is especially marked in the region between the shoul- ders but it may become genera- lized, a prominent characteristic of "vagabond's ; Ac- cording to Dubre and Beille, this melanoderma is due to a toxic substance secreted by the lice, which indirectly provokes the formation of pigment. Control measures, in the case of the body louse, consist in boiling or steaming the clothes or in some cases, sterilizing by dry heat. The dermatitis may be relieved by the use of zinc-oxide ointment, to which Pusey recommends that there be added, on accoimt of their parasiticidal properties, sulphur and balsam of Peru, equal parts, 15 to 30 grains to the ounce. Phthirius pubis (= P. wgrnnafc), the pubic louse, or so-called "crab louse," differs greatly from the preceding in appearance. It is characterized by its relatively short head which fits into a broad depression in the thorax. The latter is broad and flat and merges into the abdomen. The first pair of legs is slender and terminated by a straight claw. The second a
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