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Show 1900.] INSECTS OF THE " SKEAT EXPEDITION." 867 been found bold enough to suggest that in life it is luminousl > being led to this suggestion, I suppose, by the lantern-like outline of the " nose" in the more highly specialized members of the family, and perhaps by the fact that some of the species at any rate are nocturnal or crepuscular, and rest by day on the trunks of trees in a very open manner. At Biserat in Jalor I was fortunate enough to observe the real use of this peculiar structural modification. On the morning of May 30th, I noticed a specimen of Hotinus spinolce seated on the trunk of a Durian tree in the village and incautiously attempted to catch it in my hand. The insect remained almost still, merely drawing in its legs towards its body and pressing the claws firmly against the bark, until I had almost touched it. Then, it lowered its head with very great rapidity, flew up into the air without spreading its wings, and alighted on the roof of a house about six feet behind the tree and considerably higher than the position on the trunk wlience it had started. W h e n it was at rest its dorsal surface had been directed towards tbe roof aud its head had pointed upwards ; but it started off at a tangent from its original station, and landed with its head, speaking roughly, at right angles to an imaginary line drawn through the main axis of the body as it had been on the tree. The insect remained on the roof without moving while I went to get a butterfly-net, in which it was easily captured by a man who swarmed up one of the house-posts. At the time I did not notice anything peculiar in the way in which this Fulgorid jumped, for there are many large species of the same family (e. g. Aphcena atomaria) which, without being provided with long noses, can leap for a considerable distance by means of their legs only ; but, as I was examining my specimen after it had died in a cyanide-bottle, I was struck by an indentation or crease that ran across the central region of the nose, at right angles to its main axis. Then I discovered that tbe chitin was flexible at this point, and at this point only ; and that if the tip of the nose and the dorsal surface of the abdomen were pressed together between the finger and thumb and then suddenly released, the insect would not fall straight to the ground, but would be propelled for some distance through the air before doing so; just as would be the case if a piece of whalebone were treated in like manner. Now supposing that the whalebone (representing the nose of the insect) was fixed rigidly to a small rigid object (the head), which in its turn was fastened by a flexible juncture to a larger rigid object (the thorax and abdomen); supposing that the larger object was then laid so that it rested for all its length along a smooth vertical support with the whalebone pointing in front of it, that the free extremity of tbe whalebone was bent downwards by some force, and that the whole structure was simultaneously shoved away from the support (as the body of 1 For a coloured picture of a luminous Fulgorid, see Donovan's 'Natural History of the Insects of China,' p. 27 ; also for much evidence as to its luminosity. PROC ZOOL. Soc-1900, No. LVII. 57 |