PHYLUM ARTHROPODA — CLASS INSECTA 



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Order Siphonaptera (Fleas).— Fleas have strong jumping legs, 

 piercing and sucking mouth parts, laterally flattened bodies, but no 

 wings. They are world-wide in distribution; about four hundred 

 species have been described. All of the species in the adult stage 

 are external parasites on warm-blooded vertebrates. They are 

 pests on cats and dogs and known to be carriers of bubonic plague. 



© 



m^^^- 



Fig. 193. — Life history of the mosquito. 1, mosquito eggs floating m the water 

 (slightly magnified) ; 2, mosquito larva or wiggler ; S, mosquito pupa or tumbler; 

 J,, adult (From Turner, Personal and Community Health, published by The C. V. 

 Mosby Company, after Turner and Collins.) 



Order Dipt era (Flies and Mosquitoes). — The Diptera may be char- 

 acterized as insects with mouth parts specialized for sucking, in some 

 species for piercing; and with only two wings, the halters or second 

 pair being vestigial structures. / 



