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Show 844 MR. NELSON ANNANDALE ON THE [DeC. 4, Almost as soon as the Mantis had settled itself on the inflorescence, a small, dark, dipterous insect, of a kind very commonly seen on the flowers of this species of Melastoma, alighted on one of its hinder legs. It was soon joined by others, apparently of the same species as itself. They settled quite indiscriminately on the petals and on the body and limbs of tbe Mantis. It was then that the significance of the black spot at tbe tip of the abdomen became apparent, for at the distance of a few feet it was impossible to distinguish it, except by its symmetrical position, from one of these small Diptera. The Mantis made no attempt either to drive off or to capture the small flies, for its motions seemed to attract rather than to repel them. After a short time a larger Dipteron, as big as a common house-fly, alighted on the inflorescence within reach of the predatory limbs. Then the Mantis became active immediately; the fly was seized, torn in pieces and devoured, notwithstanding the presence of a large crowd of natives who had collected to w7atch what was happening. I did not see Hymenopus actually catch au insect on its own person ; but very probably this was owing to the short duration of m y observations. The smaller Diptera were unable to discriminate between real and simulated vegetable tissue, and there is no reason to suppose that the larger ones are more intelligent. I was unable to detect any secretion from the integument or any part of the body of the Mantis which might have attracted them. It is quite probable that they acted gratuitously as lures for its prey, in that they made it appear that there was no trap set, if they did not form an actual bait for predaceous insects. After the Mantis had been on the watch for some little time, I noticed that the abdomen was drooping slightly and was gradually coming to lie in line with the thorax. As it did so, the brown lines on its dorsal surface came into sight, and they grew7 more conspicuous the more it drooped. At last, only a very few minutes after I had first noticed this movement, the Mantis gave a sudden leap into the air and alighted on the ground at the distance of several feet from the place where the base of the stem would have been had it leaped from a real bush of the " Rhododendron." It then staggered quietly away along the ground. When interrupted in its progress it gave a short jump ; but it was easily recaptured, as its leaping powers were chiefly developed in tbe direction of jumping to tbe ground from a height. I was able to watch this drooping of the abdomen and final hasty desertion of the flowers on four separate branches. In each case the process commenced when the flowers began to droop, and occupied, perhaps, two minutes in completion. The drooping of the abdomen was primarily a preparation for leaping. Of that I have no doubt, for the body was bent again the moment the insect reached the ground, almost as if it were brought into position by the action of a powerful spring. Whenever the Mantis gave one of its short jumps on the level, the body Avas previously straightened with almost the same rapidity of action. |
