DIPTEBA 129 fithout legs, generally whitish, and vary ex- eedingly in form and habits. The larvae of the mosquito are aquatic, breathing with the head downward through the tubular tail sur- rounded with feather-like appendages, and the pupae tumble about in water by means of two oval fins. These larvae, and those of most Hies which have four or six bristles in the pro- boscis, have a distinct horny head, and cast their skins to become pupa?, which are gener- ally brownish ; many have thorns and prickles on the body by which they work their way out of their coverings ; a few cover themselves with silken webs and spin cocoons. The larvse of other flies, with a soft retractile head, living by suction, increase rapidly in size, and change their form without casting off their skins, which shorten and harden, forming a case within which the larva changes into a pupa, which comes forth a fly by forcing off one end of the case. Though this order contains the bloodthirsty mosquito, the disgusting flesh fly, and many insects depositing their eggs in the bodies of living animals, it is most use- ful, supplying food to insectivorous birds, and consuming decomposing animal and vegetable substances. Their life in the perfect state is short, very few surviving the rigor of win- ter. Among the genera with rnany-jointed antenna3 the following are the most interesting and best known : Culex (Linn.) contains the well known gnats and mosquitoes, whose larvae and pupae are so common in stagnant water, called wigglers and tumblers, and whose adult females pierce with their lancets and annoy by their nocturnal hum the human race from Lapland to the tropics; the best known species are the 0. pipiens of Europe, and the 0. Americanus of this country, which is probably distinct. The genus cecidomyia (Latr.) includes many species interesting to the agriculturist, as the Hessian fly (G. de- structor, Say), the wheat fly ( 0. tritici, Kirby), and the willow-gall fly (C. salicis, Fitch), in- jurious in the larva state. The genus tipula (Linn.), especially T. oleracea (Linn.), com- monly known in England by the name of Har- ry Long-legs, is noted for its depredations in the larva condition on the tender roots of meadow plants. In the gGmissimulium (Latr.) are the black fly and the midges of the northern parts of America. The black fly (S. molestum, Harris) fills the air during the month of June in Canada and the northern states ; it flies in the daytime, and is so sav- ,age that every bite draws blood, sometimes accompanied by considerable irritation; it is black, with transparent wings, and about T V of an inch long. After continuing through June, it is followed by another species (S. no- civum, Harris), called "no-see-'em" by the In- dians of Maine from their minuteness; they come forth toward evening, creep under any kind of garment, and produce a sharp, fiery pain without drawing blood; they are very troublesome in July and August. Among those with few joints in the antennae is the genus tdbanus (Linn.), which contains the large horse flies, as T. bovinus (Linn.), dark brown, an inch long, common in Europe, where there are more than 40 other species. The most common American species is T. atratus (Fabr.), black with a whitish bloom on the back ; the eyes are very large, shining black, with two jet- black bands across them ; it is about an inch long, with an expanse of wings of two inches. The orange-belted horse fly (T. cinctus, Fabr.) is smaller and less common, black, with the first three rings of the body orange. A smaller species is T. lineola (Fabr.), with a whitish line along the top of the hind body. In sum- mer these flies are very troublesome to cattle and horses, being able to pierce through the thickest hide with their six-armed proboscis ; a strong decoction of walnut leaves, applied as a wash, is said to keep them off. The golden- eyed forest flies (chrysops, Meig.) are known by their brilliant spotted eyes and their banded wings ; smaller than horse flies, they resemble them in their habits, frequenting woods and thickets in July and August ; some are wholly black, others striped with black and yellow. The bee fly (bonibylius cequalis, Fabr.) flies with great swiftness through sunny paths in the woods, hovering over flowers and sucking their honey, like humming birds ; it is about three eighths of an inch long, shaped like a humble- bee, and covered with yellowish hairs ; the ex- panse of the wings is about an inch ; they are divided longitudinally into two equal parts by the colors, the outer half being dark brown and the inner colorless. Among the flies which prey on other insects, seizing them on the wing or on plants, is the genus midas (Latr.), of which the orange-banded species (M. filatus, Fabr.) is sometimes 1 in. long and 2 in. in expanse of wings; the general color is black; it frequents the woods in July and August, where it may be often seen flying or basking in the sun ; the larva is a cylindrical maggot, growing to the length of 2 in. ; the pupa mea- sures 1 in. in length, is brown, with forked tail, eight thorns on the fore part of the body, and numerous sharp teeth on the edges of the abdominal rings; it pushes itself half out of its hole when the fly is about to come forth. The genera laphria (Fabr.) and asilus (Linn.) are also predaceous in the winged state ; in the former the antennae are blunt -at the end, in the latter slender-pointed; the former resemble large humblebees in their thick and heavy bodies and legs. In the larva state these asil- ians live in the ground, where they do much mischief to the roots of plants. The soldier flies (stratiomydce) have two spines on the hinder part of the thorax ; the proboscis con- tains only four bristles, and ends with fleshy lips adapted for sucking vegetable juices ; they are fond of wet places, and their larvae live in stagnant pools, some thrusting their breathing tube out of the water ; they undergo transfor- mation within the hardened larval skin. The
