Page:The New International Encyclopædia 1st ed. v. 14.djvu/68

* MOSQUITO. 54 MOSQUITO (Sp., Port, mosquito, diminutive of iiioxcu, lly, from Lat. musca, fly). A biting fly of the family Culicidic. Thuse flies belong to the group of nemocerous Diptera, anil their near- est allies are the crane-flies, the midges of the families Dixidse, Stenoxenida-, and Chironomidje, the fungus-gnats, gall-gnats, and motli-llies. from all of which true mosquitoes are distinguished by the fact that the veins of the wing and the body itself bear flattened scales, readily perceived under a low power of the microscope, 'the fam- ily is a large one, and includes 22 genera and about 300 species. The number of described species has doubled within the last few years, since especial attention has begun to be paid to this gi-oup, and activity in research is now so great that it is probable that it may again be doubled before the mosquito fauna of the globe is fairly well known. GKOfiK.M'uic DiSTRiBtTlON. The mosquitoes form a cosmopolitan group, and extend practi- cally to all known portions of the globe. Certain species are excessively abundant in the Arctic MOSQUITO. ATLANTIC COAST MOSQUITO (Culex solkitaus). regions, while the greatest number of species is to be found in the tropical and subtropical life- zones. Certain of the genera are very widely distributed, the typical genus. Culex, being found practically everywhere. Anopheles is represented in all regions except the Boreal and the Arctic; Stegomyia occurs in Southern Europe, Xorth, South, and Central America. West Indies, Afri- ca, India, Malay Archipelago, Eastern Asia, and Australasia. A similar distril>ution is found with others of the less conspicuous genera. Cer- tain species are also of almost world-wide dis- tribution, and this is doubtless largely due to the ease and frequency with which mosquitoes are transported by seagoing vessels ami liy rail- way trains, and to the extraordinary facility with which they accommodate themselves to a nov- el environment. It is a well-substanti- ated fai't, for exam- ple, that there were no mosquitoes in the Hawaiian Islands until they were brought there by sailing vessels. Cer- tain species have a ""^'^''i?. "^a^utcn^U"'""''- rcnarkable r a n g e through different life-zoni'S, and the group as a whole has only a slight faunistic value. Culex cnnlniis, forexample, occurs in Canada and the United States, through- out Europe, and in Southern India; Culex pi- piens occurs throughout Europe from Scandi- navia to Malta, all over Nortli and Central America and the West Indies, and is also found in Oriental regions. Classification. The family has been divided MOSQriTO OK YELLtlW KEVKR {Stegouij-ia fitsciata). by Theobald into six subfamilies. Anopheles, Jlegarhinus, Culex, .Edomyia, Trichoprosoon, and Corethra being the typical genera of these sub- families. The last named, however, has a short proboscis not formed for piercing, and does not belong to the bit- ing mosquitoes proper. The char- acters which have been relied upon mainly in the dif- ferentiation of the genera have been the comparative length of the palpi in the difl'ereiit sexes, the charac- ter of the terminal joints of the palpi, the relative pro- portions of certain of the cells of the wings, the characters of the scales of the legs and head, the bristles upon the metanotum, and certain other points connected with the relations of the veins of the wings. The species for the most part have been sepa- rated upon colorational characters, although cer- tain characteristics of the wing-venation are specific rather than generic, and the study of the body scales reveals specific characters. There are also some interesting characters connected with the teeth of the foot-claws which are both specific and generic. Lli'E Hlstohv. Jlosquitoes in their early stages are all aquatic. The larviE need a cer- tain amount of standing water for their develop- ment. The eggs are laid by the adult insects, in the majority of eases upon the surface of stand- a y.iiii or .vNornKLES. n, upper enrface: b, uiulcr surfucp. These eg^ float to discouiiected masses. (Giwatl.v niagiilfled.) ing water. They may be laid upon end, at- tached side by side in raft-shaped masses, as in Culex pipicits and as in the genus Uranotienia, or they may be laid singly on their sides, as in Anopheles, Stegomyia fasciata, Psorophora, and several species of Culex. They may also be laid upon moist earth in swampy places, as with Culex soUciluils, or upon the leaves of pitcher- plants, as with ll'.i/fonii/m Smithii, hatching in these eases when water eventually reaches them. The eggs of some species, as those last named and f>li<jomi/iii fasciata, will bear desiccation; but the vitality of others, as those of Anopheles, is destroyed when they are removed from the water for any length of time. The egg stage is temporary with perhaps the majority of species, but with" others it is much longer, and may be the hibernating stage with certain forms. The larva is an active and voracious little creature, and is commonly known as a 'wiggler' or "wrig-