Why are certain insects termed walking leaves ?

Because their wing-cases, not only in colour, but in texture, and even in veining, are so exactly like leaves, from the fresh green of those newly expanded, to the faded brown of those withered and fallen, that botanists themselves might be deceived, if they were detached from the insects, and exhibited as real leaves. Among locusts alone we find the various species with wing-cases resembling, in this manner, the leaves of the laurel, the myrtle, the citron, the lily, the sage, the olive, the camellia, thyme, and grass. The spectres, on the other hand, resemble the small branches of trees with their spray ; and so minutely detailed is this mimicry, that the very snags and knobs, as Kirby and Spence remark, are accurately imitated. The caterpillar of the swallow-tail moth also resembles a walking branch, the ringed bulgings of the body being precisely like those of an elder branch, while the longitudinal stripes are like the cracks in the bark.

The mantis of this tribe is found in China and South America, and in the latter country many of the Indians believe that mantes grow on trees like leaves, and that having arrived at maturity, they loosen themselves, and crawl or fly away.

Why is this species also called the religious or praying mantis?

Because it is of slender shape, and in its sitting posture holds up the two fore-legs slightly bent, as if in an attitude of prayer; whence vulgar superstition has held it as a sacred insect; and a popular notion has prevailed, that a child or a traveller having lost his way, would be safely directed, by observing the quarter to which the animal pointed, when taken into the hand.

According to the latest classification, mantes have been divided into the two families of the mantida and phasmida, founded on a difference in the structure of the foot or leg; this member, in the former, being raptorious, is provided with a sharp claw, and a hollow on the leg and thigh, and a double series of spurs, for the better securing its prey; and in the latter, being destitute of any such peculiarity. One of the species, (gongylodes ) when alive and fresh, resembles a blade of grass, differing in colour according to the season, being green and succulent in the rains, and in dry weather so much like a withered straw, that it can with difficulty be distinguished. They are very ferocious, and in China the fighting mantis forms as much the favourite amusement of boys, who carry them about in cages for the purpose, as cock-fighting in England. - Trans. Asiatic Soc. Calcutta.