MOSQUITO.
Not satisfied with piercing the flesh with their sharp proboscis, which at the same time forms a kind of syphon through which the blood flows, these malignant gnats, of which there are many species, inject a poison into the wound, which causes inflammation, and prolongs the pain.
In Angola, Dr. Livingstone found the banks of the river Seuza infested by legions of the most ferocious mosquitoes he ever met with during the course of his long travels. ‘Not one of our party could get a snatch of sleep. I was taken into the house of a Portuguese, but was soon glad to make my escape, and lie across the path on the lee-side of the fire, where the smoke blew over my body. My host wondered at my want of taste, and I at his want of feeling; for, to our astonishment, he and the other inhabitants had actually become used to what was at least equal to a nail through the heel of one’s boot, or the tooth-ache.’
‘He who has never sailed on one of the great rivers of tropical America, the Orinoco, or the Magdalena,’ says Humboldt, ‘can form no idea of the torments inflicted by the mosquitoes. However accustomed the naturalist may be to suffer pain without complaining, however his attention may be riveted by the examination of some interesting object, he is unavoidably disturbed when Mosquitoes, Zancudos, Zejens, and Tempraneros cover his hands and face, pierce his clothes, or creep into his nose and mouth. In the missions of the Orinoco, in these small villages, situated on the river banks and surrounded by interminable woods, this plague affords an inexhaustible subject for conversation. When two people meet in the morning their first questions are—‘How did the Zancudos behave last night?’ ‘How are the mosquitoes to-day?’
At the mouth of the Red River the unfortunate inhabitants lay down at night upon the ground, and cover themselves with three or four inches of sand, so that only the head remains free, over which they spread a protecting cloth. Above the influx of the Rio Arauca into the Orinoco, at the cataracts of Baragnon, the atmosphere up to a height of 15 or 21 feet, is filled with a dense mist of stinging insects. Placing oneself in some dark spot, for instance in one of the deep hollows formed in the cataracts by mounds of granitic blocks and looking towards the opening illumined by the sun, one sees whole clouds of mosquitoes, increasing or diminishing in density as the creatures in their slow and rhythmic motions now draw more closely together, and then again separate. In Esmeralda, at the eastern extremity of the Upper Orinoco, the mosquito clouds are almost as thick as at the cataracts. When the superior of the monastic order to which the mission belongs, wishes to punish a lay brother, he sends him to Esmeralda, or, as the monks facetiously remark, ‘condemns him to the mosquitoes.’
It is a well-known fact that the various species of gnats or flies comprehended under this general name, do not associate, but appear at different times of the day. As often as the scene changes or as ‘other insects mount guard,’ one enjoys a few minutes’ rest; for after the retreat of one host, its successors are not immediately on the spot. From half-past six in the morning till five in the afternoon the air is filled with mosquitoes of the genus Simulium. An hour before sunset, these are replaced by a small species of Culex called the Tempraneros or early-risers, as they also show themselves at sunrise. Their stay in the afternoon scarcely lasts an hour and a half, and then one feels soon after the painful sting of a larger Culex—the Zancudo—who, plunging his blood-thirsty proboscis into the skin, causes an excruciating pain. The Zancudo, a ‘child of the night,’ disappears at sunrise, and then makes place for the matutinal Tempranero. As all these winged tormentors spend the greater part of their lives in the water, we cannot wonder that their numbers diminish as the distance from the banks of the rivers intersecting the forests increases. Their favourite resorts are the places where their transformation takes place, and where they on their part are soon about to lay their eggs. The mosquito clouds hover only above or near the waters, and it would be a great error to suppose that the vast forests extending between the river valleys are all equally infested with this insect plague.
From time to time the mosquitoes migrate like the social stentor monkeys. Formerly no other Culex was known at Simiti on the Magdalen river but the small species called Zejen. The people slept unmolested, for the Zejen is a diurnal insect. But in 1801 the great blue-winged Zancudo made his appearance in such numbers that the poor inhabitants of Simiti could find no rest at night.
Slight differences of climate or food seem to have an influence on the intensity of the poison which the same species discharges through its serrated proboscis. One cannot refrain from smiling at the disputes of the missionaries about the size and voracity of the mosquitoes in different parts of the same river. In a land so completely severed from the rest of the world, this forms the favourite subject for conversation. ‘How much I pity you,’ said the missionary from the falls as he took leave of his colleague at the Cassiquiare; ‘you are like me, alone in this land of jaguars and monkeys, but as to my mosquitoes I can boast that one of mine is a match for three of yours.’
This unequal voracity of the insects in different places, this various intensity of poison in the same species, are very remarkable, but similar phenomena are met with in the classes of the large animals. In Angostura the crocodile attacks man, while in New Barcelona people bathe in his presence without fear. The jaguars on the isthmus of Panama are cowardly when compared with those of the Upper Orinoco; and the Indians know very well that the monkeys from one part of the country can easily be tamed, while individuals of the same species caught elsewhere will rather die of hunger than submit to captivity.
Whoever has sojourned in a mosquito land knows that there is no radical remedy against them. The Indians who besmear their body with arnatto or turtle fat, slap every moment with their flat hands on their shoulders, back, and legs as often as if they were not painted at all. On the banks of the Amazons the people use cow-dung burnt at their doors, to keep away the praya or plague, as they very justly term the mosquitoes. In the evening every house and cottage has its pan of dung smouldering in the verandah and emitting rather an agreeable odour—but where the insects are very numerous and bloodthirsty this fumigation also is of no avail.