Page:The Zoologist, 4th series, vol 3 (1899).djvu/379

Rh at the distance of even a few yards." This observer, however, at the same time refers to the statement of Bigg Wither, that this very insect is called the Whip-butterfly, owing to the sharp whip-cracking sound made by its wings when battling with its fellows in the air, and that this sound makes it the easy prey of a forest-bird, locally known as the "Suruqua," who thus detects and secures it. Here the apparent protection, by "protective resemblance," is invalidated by a peculiar and unusual sound-producing quality, which is as equally dangerous as its colour is reported protective. A similar remark may be made as to the musical Cicadidæ. How often have the usual green and brown colours of these insects been adduced as an example of protective resemblance, and not without reason if we regard only the difficulty of distinguishing them on the branches or leaves on which they rest. But when we desire to capture them, their shrill noise proclaims their retreat, and their assimilative colouration avails them little. This has frequently been the experience of the writer when in South Africa. Mr. Burr writes:—"I have often stalked down our large Locusta viridissima, L., and have usually found it on a bed of nettles or thistles, in the middle of a corn-field, or in stubble, invariably much farther away than I at first expected. The sound appears to come from almost beneath one's feet, but, on walking straight towards it, seems to recede into the distance, until it suddenly strikes the ear, very harshly and shrilly at close quarters. As soon as the would-be capturer approaches the sound ceases, and the insect remains invisible. The assimilation of the green colour of the insect and the green surroundings, which it always chooses as a band-stand, is so close, that it is almost impossible to detect the creature until it recommences to chirp, when the rapid movement of the elytra betrays its whereabouts." Frank Buckland wrote similarly of the Green Tree-Frogs of Germany:—"I have frequently heard one singing in a