Grown-up insects seem to be very short of legs compared with many of their distant relatives. Thus, while no member of the insect tribe—when grown up—has more than six legs, the Centipede or the Millipede may, as their names imply, possess a far greater number—as many, indeed, as two hundred and forty-two! But there is one curious likeness between the legs of the insects and those of their relatives—the number of pairs of legs is always odd. The insect has three pairs; the centipede and millipede have a very variable number, ranging from fifteen to one hundred and twenty-one pairs!

We have seen how wonderful the foot of the fly is, with its two sticky plates for smooth surfaces, and its two claws for rough ones. The Honey-bee has very similar feet, but the two plates are joined to form one! As in the fly, when climbing rough surfaces the flat plates are raised up, and the claws used instead; but when a smooth or slippery place has to be crossed, the claws are pulled backwards and the plates are brought down.

The legs of insects vary much, according to the purpose for which they are used. Thus, the Gnats, which spend the greater part of their time on the wing, have long slender legs, suitable for breaking the shock of alighting. Whilst in other insects the legs are used for all kinds of work, such as seizing prey, carrying it, climbing, digging, and so on. When this is the case the legs are provided with spines, or bristles.

In the Mole Cricket (fig. 1) the fore-legs are very strong, being short and broad, and ending in a broad comb-like plate, which is used for digging. They are very like the great digging paws of the mole.

The exact way in which insects walk is not easy to describe, and much study has been given to this most puzzling subject. Many devices have been adopted to make the insect draw a map of its course. In one instance the legs of a slow-walking beetle were painted, and the insect was then made to walk upon a clean sheet of paper; the track made by each leg being distinguished by the use of a different colour.

From this and other experiments it appears that there are always three legs in motion at the same time, or nearly so; meanwhile the remaining three legs support the body. First (as in fig. 2) the left fore-leg steps out, then the right middle-leg and the left hind-leg. Then the movement is taken up by the legs of the opposite side of the body, and so on.

If the movement of the legs in the six-legged insects is difficult to find out, what shall we say when the centipede (fig. 3) and millipede come to be examined? These, though not insects, are nearly related to the insects, and since they are common in our gardens, must be referred to here.

According to the lines of a humorous poem, the centipede was said to have been—

The last pair of legs in the centipede and millipede are never used for walking, and are generally much longer than the rest. In a South American species they are provided with delicate nerves, and are used as antennÆ or 'feelers,' so that the animal is armed with organs of touch at each end of the body! In one kind of millipede, in the male the last pair of legs has a sound-producing apparatus, consisting of a ridged plate, which, by being rubbed against a set of tiny, bead-like bodies set in the surface of the last shield covering the body, produces a peculiar noise.

Centipedes and millipedes generally shun the light, and hide under stones and in crevices during the day. But there are some which love the sunlight. These kinds are remarkable for the great length and slenderness of the legs, which they part with readily when handled! Most of these long-legged species are brightly coloured with black and yellow stripes or spots. In their native haunts these creatures may be seen darting about after their prey in the sun, heedless of the notice they attract by reason of their pretty colours. Few birds or beasts would think of eating them, for these creatures have a providential instinct which tells them that the gaudily-coloured animals are generally very nasty to the taste!

W. P. Pycraft, F.Z.S., A.L.S.