PARASITES OP ANIMALS. 



cally developed. The jaws are used for biting and cutting the 

 materials used in constructing their nests ; the maxillae are 

 used in manipulating and arranging ; the tongue is used for 

 lapping up honey and other liquid food. The Iarva3 are gen- 

 erally soft, footless, and white, but those of the saw flies re- 

 semble caterpillars, and have numerous abdominal legs. 



II. Diptera (two-winged). Insects belonging to this order 

 have but one pair of wings. The three regions of the body 

 are very distinct. The common house-fly, meat-flies, mos- 

 quito, Hessian-fly, wheat-midge, onion-fly (figure 9), bot-fly, 

 Fig. 9. horse-fly, and the fleas 



are examples. The 

 mouth organs- corres- 

 pond in number with 

 those of the Hymen- 

 optera, but the mandi- 

 bles and maxillce are 

 usually formed like 

 long sharp lancets, as 

 in the horse-fly (fig. 



10), or have the shape of slender and 

 sharp piercing organs, as in the mosquito. 

 The labium and tongue together generally 

 form a long proboscis, often with the 

 tongue curiously bilobed and expanded at 

 the end as in the horse-fly and house-fly. 

 The sharp mandibles and maxillaB are used 

 to penetrate the skin of animals, or the 

 bark of plants, and rind of fruits, and the fleshy tongue is 

 used to suck up the blood or other liquid food. The larvae 



eyes ; b, clypeus ; c, the three simple eyes or ocelli ; d, the antennae ; e, labrum or 

 upper lip ;.f, mandibles ; h, maxillary palpi, borne upon the base -of the maxillae 

 i, which are slender and hairy ; j, labial palpi ; k, ligula or tongue ; /, palpifer ; 

 m, paraglossae or lateral lobes of the ligula. From Packard's Guide, after New - 

 port. 



FIGURE 9. Onion-fly (Anthomyia ceparum), considerably enlarged, with larvae, 

 a and 6. From Packard's Guide. 



FIGURE 10. Head of Green-head fly or Horse-fly (Tabanus lineola Fabr.), much 

 enlarged ; a, antennae ; m, mandibles ; mx, maxillae ; mp, the large, two-jointed 

 maxillary palpi ; /, the ligula or tongue ; lb, the labrum. From Packard's Guide. 



Fig. 10. 



