CHAPTER XXV
One remark—Phosphorescent insects—Glow-worms and fire-flies—Fiery courtship—A beetle with three lamps—Travelling by beetle-light—The great lantern-fly controversy—Is it luminous?—Madame Merian’s statement—Contradictory evidence—A Chinese edict—Suggested use of the “lantern”—Confirmation required—Luminous centipedes.
NO marine insect—this is the remark—is phosphorescent—that is to say, as far as I know, which is a very saving clause indeed. This seems curious, because, as everyone knows, other sea-dwelling creatures are, producing most wonderful and beautiful effects, and, moreover, the luminous property is active in many terrestrial insects. Of these the glow-worm is a familiar and, though, perhaps, the humblest, a very beautiful example. At any rate, there are insects of the glow-worm family whose fires are far less “ineffectual,” or, to speak more truly, far outglow those of our own species. What, for instance, can be more gorgeous than the green or orange lights—for they differ in colour according to the sexes—with which the nights and the rich vegetation of the West Indies are brilliantly, yet softly, lit up? Nothing, surely, if it be not the name of the creature producing such splendour, which is Pygolampis xanthophotis[[146]]—not one syllable less.
Whether it is the male or the female that gives out the green or the orange light, I do not know, nor in my opinion do various monographists in various encyclopædias and text-books, though they make no such avowal, but content themselves with not saying. However, it is not a matter of importance except to the insect producing it, in whose breast the one or the other colour arouses very different sensations—rivalry or love. For there is no doubt now that these lovely illuminations, as well as those of our own glow-worm and of every other light-bearing creature, have relation to the needs and wants of their producers, to whose æsthetic sense, and not to ours, they are intended to appeal. That they appeal also to our own is a mere irrelevant side-issue, not considered, so to speak, by the force under whose pressure these beauties were called forth, and not of the smallest consequence. It was not always thought so, and were the pride of man reachable by such considerations it might humiliate us to reflect that displays, which in real beauty immeasurably surpass our clumsy illuminations and fireworks, are made nightly, not for our eyes, but for those of a beetle.
INSECTS THAT CARRY LAMPS
The glow-worms in this picture are rather larger than life. The male insects have wings; it is the females chiefly, if not solely, that emit the soft, beautiful light.
Gilbert White, however, in the eighteenth century, exclaims amidst some very pleasing verses: