Page:Popular Science Monthly Volume 16.djvu/810

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THE POPULAR SCIENCE MONTHLY.

A relative of the dragon-flies, the ant-lion, when in the larval state, digs a conical pitfall, at the bottom of which it lies buried, with only its strong jaws projecting. Here it patiently waits for an ant or some small creature to tumble in. If the struggling animal seems likely to clamber out, the ant-lion hurls sand at it to bring it within reach of the fatal jaws, where it is surely lost.

Ants sometimes undertake the dairy business. Being exceedingly fond of a milky fluid which exudes from two tubes situated on the hinder part of the bodies of certain plant-lice, called aphides, to procure it they resort to measures strangely intelligent for even the proverbially wise ant. They have been known to build mud stables in which the aphides were kept as stalled milch-cows. To cause the flow of milk, the ants irritate or rub the tubes with their antennæ.

Fig. 6.—Ant milking an Aphis.

With few exceptions fishes depend upon their numerous teeth for seizing food. The sturgeon is toothless, and draws in its food by suction. A single long tooth is used by the hag-fish to transfix its victim, while it bores the flesh with a long, spiny tongue. The angler lies half concealed by sand and weeds, with its enormous mouth agape ready to seize any small fish which may incautiously venture near. Upon its nose is a long, flexible spine, with shiny tip, which, waving in the water, decoys small fry to their death.

King of fishes, by virtue both of size and ferocity, is the rapacious shark. This terror of the sea has its mouth armed with hundreds of teeth, triangular in outline and serrated on the edges. There are several rows, and, as the outer old teeth drop away, others rise into position to take their places.

In Japan is found a beautiful fish which has a sort of gun for bringing down insects. It does not have to wait, like other fishes, for the fly to fall into the water by accident. Seeing one lighted near the water, the chætodon gently approaches, and, aiming its beak, blows a drop of water with unerring aim, knocks the unsuspecting fly off its perch into the stream, and devours it, doubtless with a relish begotten