Every one knows the climbing-bittersweet, or "waxwork" (Celastrus scandens), with its bright berries hanging in clusters in the autumn copses, each yellow berry having now burst open in thin sections and exposed the scarlet-coated seeds. Almost any good-sized vine, if examined early in the months of July and August, will show us the thorns, and more sparingly until October, and queer thorns they are, indeed! Here an isolated one, there two or three together, or perhaps a dozen in a quaint family circle around the stem, their curved points all, no matter how far separated, inclined in the same direction, as thorns properly should be. Let us gently invade the little colony with our finger-tip. Touch one never so gently and it instantly disappears. Was ever thorn so deciduous? And now observe its fellows. Here one slowly glides up the stem; another in the opposite direction; another sideways. In a moment more the whole family have entirely disappeared, as if by hocus-pocus, until we discover, by a change of our point of view, that they have all congregated on the opposite side of the stem, with an agility which would have done credit to the proverbial gray squirrel.
This animated thorn is about a quarter of an inch long, and dark brown in color, with two yellowish spots on the edge of its back.
Nor is this all the witchery of this bittersweet thorn. It is well worth our further careful study. Seen collectively, the thorny rose branch is instantly suggested, but occasionally, when we observe a single isolated specimen, especially in the month of July, he will certainly masquerade in an entirely new guise. Look! quick. Turn your magnifier hither on this green shoot. No thorn this. Is it not rather a whole covey of quail, mother and young creeping along the vine? Who would ever have thought of a thorn! Turning now to our original group, how perfectly do they take the hint, for are they not a family of tiny birds with long necks and swelling breasts and drooping tails, verily like an autumn brood of "Bob Whites"?
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But the little harlequin is as wary a bird as he was a thorn! No sooner do we touch his head with our finger than with an audible "click" he is off on a most agile jump, which he extends with buzzing wings, and is even now perhaps aping a thorn among a little group of his fellows somewhere among the larger bittersweet branches.
It is only as we capture one of the little protean acrobats between our finger-tips and examine him with a magnifier that we can really make "head or tail" of his queer anatomy. Even thus enlarged it is difficult to get entirely rid of the idea of a bird. I have shown a group of the insects in various attitudes, the position of the eyes alone serving as a starting-point for our comprehension of his singular make-up. The tall neck-like or thorn-like prominence is then seen to be a mere elongated helmet, which is prolonged into a steep angle behind, so as to cover the back of the creature like a peaked roof, a feature from which the scientific name of this particular group of insects is derived, Membracis, meaning sharp-edged, the sides of the slope being covered by the close-fitting wings, which, though apparently compact with the body of the insect, are nevertheless always available for instant and most agile flight. We now discover two pairs of stout legs just beneath the edge of the wings, a third more slender pair being concealed behind, ready for immediate use in association with these buzzing wings when the whim of the midget prompts it to leap.
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This insect is the tree-hopper, and is but one of many equally curious and mimetic species to be found among the smaller branches of various trees and shrubs.
Our largest membracis is to be seen-with difficulty-on the terminal twigs of the locust-tree, its outlines so exactly imitating the thorny growths of the branch as to escape detection even by the closest scrutiny. Another remarkable species is a protégé of the oak, so closely simulating the warty bark of the smaller branches upon which it is found that our eyes may rest upon it repeatedly without recognizing it. The life history of these singular insects is quite similar, and is soon told. The membracis belongs to the tribe of "Bugs," Hemiptera, which implies that it possesses a beak instead of jaws, by which it sucks the sap of plants, precisely like the aphis, or plant-louse. This tiny beak we can readily distinguish bent beneath the body of our bittersweet hopper. Inserting it deep into the succulent bark, the parasite remains for hours as motionless as the thorn it imitates, the lower outline of its body hugging close against the bark. The curious suggestion of the thorn is produced not only by the outline, but by the curious fact that the hopper never sits across the twig, but always in the direction of its length; and, what is more, the projecting point of the thorax is always directed towards the end of the branch, or direction of growth. It is no easy thing even for the casual botanist to determine this nice point in a given segment of a bittersweet branch placed in his hand, the position of the chance leaf or leaf scar being his only guide. But the Membracis binotata rarely-indeed never, so far as I have examined-makes a mistake. Thus the wandering spray of bittersweet, recurve and twist upon itself as it may, will always disclose the little hopper or colony of them headed for its tip.
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But I have omitted to mention one singular feature which is the usual accompaniment of my group of hoppers, and is, indeed, the most conspicuous sign of their presence on any given shrub. In the cut below I have indicated a short section of a bittersweet branch as it commonly appears, the twig apparently beset with tiny tufts of cotton, occasionally so numerous as to present a continuous white mass, usually on the lower side of the branch, where its direction is horizontal. They are thus easily seen from below, and a closer examination will always reveal one or more of the black animated thorns in their immediate vicinity, suggesting the responsible source. These tufts are pure white, a little over an eighth of an inch in length, and semicircular in vertical outline. The natural presumption is the idea of maternity, the mother hopper guarding her bundles of white eggs, or her infant hoppers, perhaps, snugly tucked up in their downy swaddling-clothes. But a closer examination completely dispels this illusion. Instead of the supposed fluffy cotton, we now discover the white substance to be of firm though somewhat sticky consistency, its surface, moreover, beautifully ridged from base to summit in parallel rounded flutings, which meet and interfold like a braid along the summit. If with a sharp knife we now cut downward through and across the mass, we find our tuft to be a mere frothy shell containing two hollow compartments, with a thin central partition extending through the whole length of the cavity. But there is no sign of an egg or other life to be disclosed anywhere, either in its substance or its concealment. What, then, is the office of this tiny fragile house of congealed foam, with its snowy aerated structure, its double arched chambers, its corrugated walls and ceilings, and missing tenant or host? Such was the riddle which it propounded to me, and guided by some previous knowledge of the habits of allied insects, I was soon enabled to witness a solution of at least a part of its mystery.
This little thorn-like tree-hopper and all of its queer harlequin tribe are near relatives to the buzzing cicada, or harvest-fly, whose whizzing din in the dog-days has won it the popular misnomer of "locust."