LIBRARY

CHAPTER XXXV
32. Order DIPTERA 1 Linnreus 1758
(Dip'ter-a, from the Greek at, aLs, twice, + 7r7"epa, wings;
referring to the single pair of wings.) Genuan, Zweifiiigler.
French, Dipteres.
Flies, Gnats, Midges, Mosquitoes, Punkies
Minute to medium-sized, diurnal, crepuscular and nocturnal, terrestrial and aquatic
insects with sucking and lapping, piercing, or vestigial mouth parts; complex metamorphosis;
thin, fragile, parchment-like integument. Head hypognathous, attached by
slender neck. Antenll!e variable, simple or with arlsta. El'os large, separate or contiguous,
rarely divided. Ocelli, usually three present. Fore wings developed for flight,
with few veins. Hind wings represented by a pair of halteras (rarely absent) or small
vestigial organs. Rarely brachypterous, apterous, or with vestigial wings. Legs short
or very long; tarsi five-segmented; one pair of claws, puivilli, and an empodium usually
present. Larvre dipteroid, usually cylindrical or spindle-shaped; segmented; with or
most often witb.out head; mouth parts inconspicuous, eyes usually absent; apodous.
Flies are a group of homogenous insects for the most part and are readily dis·
tinguished by the single pair of wings and the characteristic form of the body
and its more or less distinct type of appendages, particularly the antennre,
mouth parts, legs, and by their movements on foot and on the wing. The adults
are among man's greatest tormentors, ever-persistent nuisances, and his most
effective enemies as carriers of innumerable agencies of disease and death.
Although no other order of insects affects the human race sO adversely, many
large families do much good in the reduction of carrion and in the destruction of
phytophagous insects that destroy agricultural crops. A few species have even
been used for food.
Flies are among the swiftest and most agile fliers and can outmaneuver any
other insect on the wing. Regardless of exaggerated claims, certain species can
probably travel 50 miles an hour which is a real accomplishment for such small,
light, and fragile bodies. While many species are more or less noiseless in the
air, most members of the group are decidedly noisy and hum with a soft or loud,
low or high-pitched tune which is somewhat characteristic of the families, and
may serve in locating the opposite sex in mating. In contrast to the swift
flights of the hunting parasitic flies are the lazy gyrations of the common housefly
in the living room and the leisurely or lively so·called mating dances of so
many gnats and dance flies. Some forms like the syrphid flies, big· eyed flies,
horn flies, and hippelates flies hover in the air above or about the contemplated
host. The members of the African genera Aenigmatias Meinert and Aenigmatistes
Shelford have neither wings nor halteres. Others are very active and
1 The manuscript of this order was read and augmented by T. B". G. Aitken.
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