Fleas Order Siphonaptera

Identification: Small wingless insects, generally less than 5 mm. and usually living as ectoparasites on birds or mammals. Body laterally flattened, rather bristly, and heavily sclerotized. Antennae short, 3-segmented, usually fitting into grooves on head. Ocelli lacking. Compound eyes present or absent. Legs relatively long, coxae large, tarsi 5-segmented. Mouth parts sucking, the palps well developed. Metamorphosis complete. Usually jumping insects.

Similar orders: (1, 2) Mallophaga and Anoplura (pp. 106, 108): dorsoventrally flattened; legs short, tarsi 1- or 2-segmented; not jumping insects.

Immature stages: Larvae are slender, whitish, and legless, with a well-developed head and 2 small hooks on posterior end of body; they are usually found in dirt or debris, often in nest of the host. Larvae feed on various organic materials and pupate in silken cocoons.

Habits: Fleas are active insects that generally move freely over body of the host and from one host to another; some may spend considerable time off the host. Eggs are laid on the host or in dirt of the host nest; if laid on the host they eventually fall off, and larvae develop off the host. Adults feed on blood of the host. Many species (including those attacking man) are not very specific in their choice of a host and may feed on various animals. Importance: Many fleas are annoying pests because of their bloodsucking habits. A few act as vectors of disease (bubonic plague and endemic typhus) and a few burrow into the skin of man or animals.

Classification: There are differences of opinion regarding the number and arrangement of the families of fleas; we follow an arrangement in which the fleas are grouped in 7 families. Families are separated principally by head and abdominal characters and on the character of various bristles. Some of these characters are difficult to see unless the specimen is mounted on a microscope slide.

COMMON FLEAS Family Pulicidae Identification: Abdominal terga 2-6 with a single row of bristles. Compound eyes well developed. Genal comb (row of strong bristles on lower front border of head) present or absent.

This is a large group, and many of its members are fairly common; the fleas most often attacking man and domestic animals, and those most important as disease vectors, belong to this family. Many are not very specific in their selection of a host,

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