PARASITES OF ANIMALS. 7 
eally developed. The jaws are used for biting and cutting the 
materials used in constructing their nests; the maxilla are 
used in manipulating and arranging; the tongue is used for 
lapping up honey and other liquid food. The larve 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 ficas 
are examples. The 
mouth organs corres- 
pond in number with 
those of the Hymen- 
optera, but the mandi- 
bles and mazille 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 maxille 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 larve 
eyes; b, clypeus; c, the three simple eyes or ocelli; d, the antennz; e, labrum or 
upper lip; f, mandibles ; h, maxillary palpi, borne upon the base of the maxillx 
i, which are slender and hairy; j, labial palpi; &, ligula or tongue; /, palpifer ; 
m, paraglosse or lateral lobes of the ligula. From Packard’s Guide, after New - 
port. 
Fieure 9.—Onion-fly (Anthomyia ceparum), considerably enlarged, with larvee, 
aandb. From Packard’s Guide. 
Figure 10.—Head of Green-head fly or Horse-fly ( Tabanus lineola Fabr.), much 
enlarged; a, antenne ; m, mandibles; mz, maxilla; mp, the large, two-jointed 
i i; i ; . From Packard’s Guide. 
maxillary palpi; /, the ligula or foneue ; aff, the, Jabram r acka: i 
