. Handbook of medical entomology. Insect pests; Insects as carriers of disease; Medical parasitology. Dogfiea (xl5). After Howard. The most common fleas infesting houses in the Eastern United States are the cosmopoHtan dog and cat fleas, Ctenocephalus canis (fig. 90) and C. felis. Their life cycles wUl serve as typical. These two species have until recently been considered as one, under the name Pulex serraticeps. See figure 92. The eggs are oval, slightly translucent or pearly white, and measure about .5 mm. in their long diameter. They are de- posited loosely in the hairs of the host and rea
. Handbook of medical entomology. Insect pests; Insects as carriers of disease; Medical parasitology. Dogfiea (xl5). After Howard. The most common fleas infesting houses in the Eastern United States are the cosmopoHtan dog and cat fleas, Ctenocephalus canis (fig. 90) and C. felis. Their life cycles wUl serve as typical. These two species have until recently been considered as one, under the name Pulex serraticeps. See figure 92. The eggs are oval, slightly translucent or pearly white, and measure about .5 mm. in their long diameter. They are de- posited loosely in the hairs of the host and readily drop off as the animal moves around. Howard found that these eggs hatch in one to two days. The larvae are elongate, legless, white, worm-like creatures. They are exceed- ingly active, and avoid the light in every way possible. They cast their first skin in from three to seven days and their second in from three to four days. They commenced spinning in from seven to fourteen days after hatching and the imago appeared five days later. Thus in summer, at Washington, the entire life cycle may be completed in about two weeks, (cf. fig. 91, 92). Strickland's (1914) studies on the biology of the rat fiea, Cerato- phyllus fasciatus, have so important a general bearing that we shall cite them in considerable detail. He fotmd, to begin with, that there is a marked inherent range in the rate of development. Thus, of a batch of seventy-three eggs, all laid in the same day and kept together under the same condi-. 91. Larva of Xenopsylla cheopis. After Bacot and Ridewood. tions, one hatched in ten days; four in eleven days; twenty-five in twelve days; thirty-one in thirteen days; ten in fourteen days; one in fifteen days; and one in sixteen days. Within these limits the duration of the egg period seems to depend mainly on the degree of humidity. The incubation period is never abnormally prolonged. Please note that these images are extracted from scanned page images that may have been d
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