The Animal Parasites of Man

by Harold Benjamin Fantham; Max Braun; J. W. W. Stephens; Fred. V. Theobald

About forty species are known in this genus, occurring in Southern Europe, Asia, Africa, Australia, the Americas, East and West Indies, and on most oceanic islands. Many of them seem to be vicious blood-suckers. They are mostly black and white mosquitoes, and several seem to go by the name of tiger mosquitoes. The genus contains the yellow fever mosquito (S. fasciata, Fabricius), the only one that need be dealt with in detail here. The chief known species tabulate as follows:—

A.	Proboscis banded.
α.	Legs basally banded.
	Thorax brown, with scattered creamy-white scales	annulirostris, Theobald.
	Thorax black, with narrow, curved golden scales	periskelta, Giles.
αα.	Legs with basal and apical banding. Fore legs with no bands; mid with apical and basal bands on first and second tarsals, hind with basal bands.
	Thorax white in front, with a brown eye-like spot on each side	thomsoni, Theobald.
AA.	Proboscis unbanded.
β.	Legs basally banded.
γ.	Abdomen basally banded.
	Thorax with one median silvery-white line	scutellaris, Walker.
	Thorax as above, but pleuræ with white lines	pseudoscutellaris, Theobald.
	Thorax similar, but two white spots near where line ends	gelebinensis, Theobald.
	Thorax with two median yellow lines and lateral curved silvery lines	fasciata, Fabr.
	Thorax with two short median lines and a white patch on each side	nigeria, Theobald.
	Thorax with large lateral white spots in front, smaller ones by wings, two narrow median lines and two posterior sub-median white lines	lilii, Theobald.
	Thorax with a white W-shaped area in front, a prolongation curved on each side enclosing a brown eye-like spot	W-alba, Theobald.
	Thorax with white frontal median spot, two large lateral spots, a small one in front of the wings, a narrow median white line and narrow sub-median ones on posterior half. Last two hind tarsi white	wellmannii, Theobald.
	Thorax brown, with broad white line in front extending laterally towards wings, where they swell into a large patch, a white line on each side just past wing roots. Last two hind tarsi white	albipes, Theobald.
	Thorax with silvery white spot on each side in front, small one over roots of wings and white over their base. Last two hind tarsi white	pseudonigeria, Theobald.
	Thorax with two lateral white spots, front ones the largest, a small median one near head, two yellow median lines, a short silvery one on each side before the scutellum	simpsoni, Theobald.
	Thorax with silvery-white scaled area in front and another on each side in front of wings	argenteomaculata, Theobald.
	Thorax with median yellowish-white line, a silvery patch on each side in front of wings extending as a fine yellow line to the scutellum, and another silvery spot before base of each wing	poweri, Theobald.
	Thorax with small grey-scaled area in front of wing roots and three short creamy lines behind	minutissima, Theobald.
	Thorax (?) denuded; abdomen black; fifth segment with yellow basal band; sixth unbanded; seventh, two median lateral white spots; eighth, two basal lateral white spots; second hind tarsal nearly all white	dubia, Theobald.
γγ.	Abdomen unbanded.
	First hind tarsal all white, second basally white, last two dark. Thorax chestnut brown, with a broad patch of white scales on each side in front and a median pale line	terreus, Walker.
ββ.	Legs with white lines as well as basal bands.
	Thorax brown, with white lines; abdomen with basal bands	grantii, Theobald.
βββ.	Fore and mid legs with apical bands, hind basal.
	Fourth tarsal of hind legs nearly all white	mediopunctata, Theobald.
	Mid metatarsi with basal pale banding, base and apex of hind, also base of first tarsal pale	assamensis, Theobald.
ββββ.	Legs unbanded.
δ.	Abdomen basally banded.
	Thorax with front half white, rest bronzy-brown	pseudonivea, Ludlow.
	Thorax deep brown, with scattered golden scales, showing two dark eye-like spots; head white, dark on each side and behind	albocephala, Theobald.
	Thorax brown with golden stripes; abdomen with narrow basal bands on fifth and sixth segments only	auriostriata, Banks.
δδ.	Abdominal banding indistinct.
	Thorax with broad silvery white patch on each side in front	albolateralis, Theobald.
δδδ.	Abdomen unbanded.
	Thorax with six silvery spots	argenteopunctata, Theobald.
δδδδ.	Abdomen with apical white lateral spots.
	Thorax unadorned, except for pale scaled lines laterally	punctolateralis, Theobald.
δδδδδ.	Abdomen with basal white lateral spots.
	Thorax with two pale median parallel lines and two silvery lateral spots	ininuta, Theobald.
	Thorax unadorned.
	A white spot middle of head	tripunctata, Theobald.
	No white spot	amesii, Ludlow.
AAA.	Proboscis yellow basally, dark apically.
	Abdomen with apical pale bands	crassipes, Van der Wulp.
AAAA.	Proboscis with median interrupted white line on basal half.
	Head black, anterior margin grey	albomarginata, Newstead.

Stegomyia fasciata, Fabricius (Yellow Fever Mosquito).

This insect, which is the proven carrier of yellow fever, is commonly called the tiger, brindled, spotted day or striped mosquito. It is also referred to by some writers as S. calopus, Meigen. It is subject to considerable variation in colour, but the thoracic markings are generally very constant. The general colour is almost black to deep brown, the head with a median white area, white at the sides and in front around the eyes; the thorax has two median parallel yellow lines, a broad curved silvery one on each side and white spots at the sides; the scales on the intervening spaces of the thorax are brown. The dark abdomen has basal white bands and basal white lateral spots. The dark legs have basal white bands, the last segment of the hind legs being all white except in a variety from South America and the West Indies (luciensis), which has the tip of the last hind tarsal dark. The abdomen may also vary in colour, some having pale scales over most of the surface (queenslandensis).

The food of the adult female consists mainly of man’s blood, but she will also feed on dogs and other animals. The male has been said to bite, but such is very unusual. This mosquito bites mainly in the daytime up till about 5 p.m.

The adults breed the first day after emergence. They may live a considerable time, Bancroft having kept females for two months in confinement. The ova are laid separately, often in chains; they are black, oval, with a reticulated membrane outside, some of the reticulated cells containing air. They may hatch in from six to twenty hours, the larval stage nine days, the pupal stage three; thus the whole cycle may be completed in from twelve to thirteen days. The ova when dry can remain undeveloped for a considerable time. The larvæ are greyish-white, with short, thick siphon, and feed at the bottom of the water, only coming to the surface now and again to breathe. This is almost entirely a domesticated gnat, seldom being found far from man’s habitations. Its larvæ occur in such small collections of water as old sardine tins, jam-pots, calabashes, puddles, barrels, wells—in fact, wherever water is held up, even to the gutters of houses. Not only are they found breeding on land, but also on board ship, although they prefer artificial collections of water. They may also breed in larger natural collections.

This insect is easily transported by steam and sailing ships and by train, and this doubtless explains its very wide distribution. The adults may live for fifty days, and it is on this account and their frequent occurrence on ships that danger lies in regard to the Panama Canal. An infected insect may leave that endemic centre of yellow fever and live until the vessel arrived at the Philippine Islands and fly ashore, and so introduce the disease for the native fasciata possibly to spread.

Roughly the distribution of this pest is as follows: Africa from South to North, but especially along the coast and up the Nile. In Asia, in India, Ceylon, Burma, Siam, along the ports of the Malay Peninsula, in French Cochin China, Philippine Islands, the Andaman and Nicobar Islands, Japan, Malay Archipelago, and East Indies, Turkey in Asia, Arabia and Palestine.