The last figure represents the common Water-gnat (Gerris), which may be seen in almost any piece of fresh water, however small. Ponds that are open to the south, and sheltered from the north wind, are its favourite localities.
It is a carnivorous being, feeding almost wholly on insects that fall into the water. In order to capture them, it runs rapidly over the surface of the water, the long slender legs distributing its weight over a large surface, and so keeping it from sinking. Only the last two pairs of legs are employed for this purpose, the first pair being held in front of the body, and used for the purpose of capturing prey.
Tree-climbing.
Another curious aid to locomotion is shown in the accompanying illustration.
In many parts of the world, where the cocoa-nut palm grows, the natives have invented a simple, but ingenious, plan for ascending the tall, curved stem. Such a thing as an upright palm-tree is unknown, and consequently the ascent of the branchless stem is not an easy task without artificial assistance.
When I treated of Warfare and the different modes of scaling walls, the climbing-spur was casually mentioned. The implement of the palm-climber, however, is simpler and more effective, as it leaves both hands at liberty when desired.
The man cuts a long piece of one of the tough and almost unbreakable creepers which festoon the trees of tropical climes. He passes it round the trunk which he wishes to climb, and fastens the ends firmly together, so as to form a large loose hoop. He then passes the hoop over his head, until it presses against his back, as seen in the illustration, and serves to support him as he leans against it.
Taking the hoop by the two sides, he lifts it up the trunk as far as he can, places the soles of his feet against the tree, and so walks up it, hitching the hoop upwards at every step. When he has reached the top of the tree, he supports himself entirely by the hoop, while his hands are at liberty to be used in getting the cocoa-nuts.
In the insect world there are many examples of support being given by a belt passing round the body.