332 THE LIVING ANIMALS OF THE WORLD 







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CICADA AND PUPJE 



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TWO-WINGED INSECTS, OR FLIES 



BY W. F. KIRBV, F.L.S 



THIS order of insects is probably one of the 

 most numerous in individuals, though it may be 

 that, when \ve know more of the insect population of 

 the world, we shall find that it is outnumbered in 

 species by the Beetles or the order to which the 

 Hires and Ants belong. It differs from all other 

 orders in possessing only two wings instead of four, 

 which is the usual number in insects. The meta- 

 morphoses are complete, and the mouth is furnished 

 with a proboscis for imbibing liquid food. Hind wiiv^s 

 are represented in many species by a pair of organs 

 called " poisers," resembling a knob at the end of a 

 stick, and other species have two small addition.il 

 lobes attached to the wing, called " winglets " ; but 

 there is no such thing as a really developed hind 

 wing in any insect belonging to the group. They 

 are always two-winged flies, except in the case of a 

 few aberrant species, such as the Fleas, in which no 

 wings, or only mere rudiments of wings, arc to be 

 met with. The Gnats, Daddy-long-legs, and House- 

 flies are among the commonest representatives of this 

 order. 



The first section of the group includes the GNATS and the DADDV-I.ONC.-I.KI.S, or CRANK- 

 FLIES, the members of which may be distinguished by having moderately long antenna:, comp< ised 

 of more than six joints, and never terminating in a bristle. They are all vegetable-feeder*. 

 with the exception of the females of gnats and sand flies, which are furnished with a lancet- 

 like arrangement for sucking the blood of warm-blooded animals. 



The GALL-FLIKS. WHEAT-MIDGES, etc., have rather long, jointed antennas, which arc not 

 feathered, though sometimes tufted on the sides, and their maggots produce small galls on 

 various trees and plants, or distort and otherwise injure them. They resemble small -M.IN. 

 and there are two particularly destructive species which attack corn in England and elsewhere, 

 the \VUEAT-.\IIIICE, an orange-yellow fly with black eyes, which produces little yellowish or 

 reddish maggots which injure the growing grain in the ear; and the Hr>-i \\ l-'i.v. which 

 is brown, and produces semi-transparent maggots, which afterwards grow darker, and when 

 full grown become pupae resembling flax-seeds. The maggots attack the 

 stalk, feeding on the sap till the stalk cracks and bends over. This is an 

 infallible sign of their presence, and of the mischief they are doing. 



Among the best-known insects of this group are the GNATS, or 

 Mos'.u n "!>, of which there arc many genera and species. There is no 

 difference, however, to permit of their being classified in two separate 

 popular categories. In England any of these troublesome insects are 

 called Gnats; out of England they are termed Mosquitoes, if we are 

 tormented by them, even though they may belong to the same species 

 as the English ones for " mosquito " is merely the Spanish word for 

 " gnat " Anglicised. 



Gnats breed in standing water, fresh or otherwise, but seem to picfcr 



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rain-water, for they are very numerous about small pools and water-butts. BROWN Musgi I 1 o 

 Consequently they were formerly far more abundant in England than at 

 present, when the fens were still undrained, and when every house had 



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