INTRODUCTION. 15 



times, however, naked, in which case the wings and the legs are 

 visible, and are found to be more or less free or unconfined. 



The two-winged insects, though mostly of moderate or small size, 

 are not only very numerous in kinds or species, but also extremely 

 abundant in individuals of the same kind, often appearing in swarms 

 of countless multitudes. Flies are destined to live wholly on liquid 

 food, and are therefore provided with a proboscis, enclosing hard and 

 sharp-pointed darts, instead of jaws, and fitted for piercing and suck- 

 ing, or ending with soft and fleshy lips for lapping. In our own per- 

 sons we suffer much from the sharp suckers and blood-thirsty propen- 

 sities of s;nats and mosquitos ( Culicidce), and also from those of certain 

 midges (Ceratopogon and Simulium), including the tormenting black- 

 flies (Simulium molestum) of this country. The larvae of these insects 

 live in stagnant water, and subsist on minute aquatic animals. Horse- 

 flies and the golden-eyed forest-flies (Tabanida), whose larvae live in 

 the ground, and the stinging stable-flies (Slo?noxys), which closely 

 resemble common house-flies, and in the larva state live in dung, 

 attack both man and animals, goading the latter sometimes almost to 

 madness by their severe and incessant punctures. The winged horse- 

 ticks (Hippoboscce), the bird-flies (Or?iithomyi<z), the wingless sheep- 

 ticks (Melophagi), and the spider-flies (Nycteribice), and bee-lice 

 (Braulce), which are also destitute of wings, are truly parasitical in 

 their habits, and pass their whole lives upon the skin of animals. Bot- 

 flies, or gad-flies, (GEstridce), as they are sometimes called, appear to 

 take no food while in the winged state, and are destitute of a pro- 

 boscis ; the nourishment obtained by their larvae, which, as is well 

 known, live in the bodies of horses, cattle, sheep, and other animals, 

 being sufficient to last these insects during the rest of their lives. 

 Some flies, though apparently harmless in the winged state, deposit 

 their eggs on plants, on the juices of which their young subsist, and 

 are oftentimes productive of immense injury to vegetation ; among 

 these the most notorious for their depredations are the gall-gnats 

 (Cecidomyice), including the wheat-fly and Hessian fly, the root- 

 eating maggots of some of the long-legged gnats ( Tipulce), those of 

 the flower-flies (Anthomyia), and the two-winged gall-flies and fruit- 

 flies (Ortalides). To this list of noxious flies, are to be added the 

 common house-flies (Muscce), which pass through the maggot state in 

 dung and other filth, the blue-bottle or blow-flies, and meat-flies 

 (Lucilice and Calliphora), together with the maggot-producing or 



