. Smithsonian miscellaneous collections. ctly parasitic but live principally in thenests of the animals on which they feed. The eggs of the fleas are generally deposited on the bodies of thehosts, but they readily fall off to the ground, into nests or bedding,or onto the floors of buildings. The young flea is a legless, wormlikelarva, which lives wherever the eggs drop, and goes through a pupalstage before becoming an adult flea and adopting the parasitic, blood-sucking habit. The fleas, therefore, are the only bloodsucking insects 84 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO4 other than t
. Smithsonian miscellaneous collections. ctly parasitic but live principally in thenests of the animals on which they feed. The eggs of the fleas are generally deposited on the bodies of thehosts, but they readily fall off to the ground, into nests or bedding,or onto the floors of buildings. The young flea is a legless, wormlikelarva, which lives wherever the eggs drop, and goes through a pupalstage before becoming an adult flea and adopting the parasitic, blood-sucking habit. The fleas, therefore, are the only bloodsucking insects 84 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO4 other than the flies that have what is called a complete metamor-phosis. The fleas as parasites mostly attack mammals, but some of themlive on birds and are particularly a pest of domestic poultry. Severalhundred species of them have been named and described. Ewing andFox (1943) record more than 200 from North America and theWest Indies. The species that commonly annoy man and domesticanimals are known as the human flea (fig. 33 A, B), the dog flea. Fig. 33.—Examples of fleas. Order Siphonaptera. A, the human flea, Pulcx irritans L., female (length a little over 2 mm.).B, same, male (length i^ mm.). C, the dog flea, Ctenocephahdes cams(Curtis), in natural position of repose, dorsal view. D, same, lateral view,more enlarged, female (length about 2 mm.). E, head, pronotum (Ni), andbase of first leg (Li) of female dog flea; note combs (ctenidia) of strong spineson lower edge of head and on margin of pronotum. (C, D, E), the cat flea, and the rat flea, but the names have littlesignificance since these fleas are promiscuous with regard to hosts. Entomologists have much discussed the theoretical question of therelation of fleas to other insects, without arriving at any consensus;the fleas remain an independent order of obscure origin. Theirfeeding apparatus has features found in diverse groups of insects,but the combination of characters is peculiar to the fleas. The head of a typical flea (fi
Size: 1861px × 1342px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorsm, bookcentury1800, bookdecade1860, booksubjectscience
