. Preventive medicine and hygiene. s jump 3 to 5 inches, never over 6. No part of the ^Formerly Loemopsylla cheopis. FLEAS 263 leg is particularly enlarged, so that the jump is made by the entire leg, asin the leaf-hopper insect, and not by the femur of the hind leg, as inthe grass-hopper. Fleas do not vary much in size. They are mostlyabout 2 to 3 millimeters long. The adult insect has a hard, stronglychitinized body. The mouth parts resemble somewhat those of the mos-quito. Both the male and the female flea are capable of piercing the skinto obtain blood and thus transmit infection. Fleas, a
. Preventive medicine and hygiene. s jump 3 to 5 inches, never over 6. No part of the ^Formerly Loemopsylla cheopis. FLEAS 263 leg is particularly enlarged, so that the jump is made by the entire leg, asin the leaf-hopper insect, and not by the femur of the hind leg, as inthe grass-hopper. Fleas do not vary much in size. They are mostlyabout 2 to 3 millimeters long. The adult insect has a hard, stronglychitinized body. The mouth parts resemble somewhat those of the mos-quito. Both the male and the female flea are capable of piercing the skinto obtain blood and thus transmit infection. Fleas, as a rule, prefercertain hosts, but are not as particular in this regard as are many para-sites. Those species which are best known are found to attack severalhosts, including man. This is one reason that makes them dangerousparasites, so far as plague and other infections are concerned. Over 300species are described. Formerly all fleas were classified in the singlefamily Pulicidae, genus Pulex; now they are arranged in many genera. g^m^ ^jfflp^™» •^A^l^r---^ )f , Fig. 42.—The Human Flea {Pulex irritans Linn.). and these genera grouped into families.^ Pulex serraticeps or Ctenoce-pJialtis cams occurs all over the world, infesting cats and dogs, also manyother animals. They are frequently brought into houses upon domesticanimals, and thus become troublesome to man. Pulex irntans is thehuman flea, sometimes called the house flea or common flea. Thefleas concerned in the transmission of plague are Xenopsylla cJieopis, theIndian rat flea, and Ceratophyllus fasciatus, the common rat flea ofEurope and North America. Plague may also be transmitted by Cteno-cephalus felis, the cat flea; Pulex irritans, the human flea; Ceratopliyllusacutus, the squirrel flea, and doubtless other genera and species. In addition fleas act as intermediate hosts for certain tapeworms(Dipylidium caninum), and doubtless are the mechanical or biologicalcarriers of other infections. Nicolle incriminates t
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Keywords: ., bookauthorwh, bookcentury1900, bookdecade1910, booksubjecthygiene
