PHOSPHORESCENCE. 



539 



vouring those troublesome insects, the inusquitoes, 

 in their habitations, which would become otherwise 

 extremely troublesome. They catch them in the 

 night by holding up a torch on some eminence, to 

 the light of which they soon come, when they are 

 beaten down with the branches of trees; or sometimes 

 one of them is held up in the fingers and moved 

 about, which will attract to the place such as are 

 near, when they are either knocked down or seized 

 with the hand. 



Fig. 21 exhibits the insect with the shell of the 

 corcelet removed on one side, so as to uncover the 

 light-emitting organ, a is the yellow transparent 

 spot of the corcelet; b, the elliptical mass of luminous 

 substance, surrounded by an irradiation of the inter- 

 stitial substance; c, the ends of the muscles which 

 are in the inside of the corcelet. Fig. 22 is a mag- 

 nified representation of the luminous apparatus; a, 

 the radiated appearance of the interstitial substance 

 around the oval mass of luminous matter: this mass, 

 it will be observed, consists of many smaller parts; 



b, represents the arrangement of the interstitial sub- 

 stance, when it passes down between the muscles; 



c, the ends of the back muscles; d, the shell of the 

 corcelet. Dr Brown was of opinion that all the 

 internal substance of this insect is equally luminous, 

 and that the yellow spots appear to emit a greater 

 degree of light, in consequence of the shell in those 

 places being thinner. He says, that if the rings which 

 cover the different parts of the body are forced a 

 little asunder, the same degree of light is emitted 

 from all the entrails indiscriminately. 



There is but little difference in the appearance of 

 the animals, and property of the light emitted by 

 the other two species of elater. The fire-fly is one 

 of the most splendid of the luminous insects. Mouffet 

 informs us, that when Sir Thomas Cavendish and 

 Sir Robert Dudley landed in the West Indies, and 

 saw an infinite number of lights sparkling in the 

 woods, they took them for Spaniards at a distance, 

 advancing upon them by torch-light, and fled to 

 their ships; but these turned out to be nothing more 

 than the fire-flies. 



This insect is of an oblong form, and an inch or 

 upwards in length. It is so strong, and exerts such 

 elastic powers, as, when placed on its back, it is known 

 sometimes to spring to the height of four or five 

 inches in recovering its natural position. Its colour 

 is brown, except the head, which is small and black- 

 ish. 



The common glow-worm (Lampyris noctiluca), fig. 

 34. During the summer season, these insects are 

 observed after sunset, in meadows, by road sides, 

 and near bushes. Among the crooked lanes, in 

 every hedge, the glow-worm lights his gem, and 



through the dark 



A moving' radiance twiiik'es. 



It is in the nights of the month of June that they are 

 most frequently to be met with. In the day-time 

 they conceal themselves amongst leaves of plants. 

 Each sex is luminous, but in the male the light is 

 less brilliant, and confined to four points, two of 

 which are situated on each side of the two last rings 

 of the abdomen. They always become much more 

 lucid when they put themselves in motion. This 

 would seem to indicate that their light is owing to 

 their respiration; in which process, it is probable, 

 phosphoric acid is produced by the combination of 

 oxygen gas with some part of the blood, and that a 

 light is given out through their transparent bodies 

 by this slow internal combustion. By contracting 

 themselves the insects have a power of entirely with- 

 drawing it: when they are at rest, very little light is 

 to be seen. Mr Templer, who made many obser- 



vations on glow-worms, says, he never saw them 

 exhibit their light at all, without some sensible mo- 

 tion, either in their body or legs: and he fancied that 

 he sensibly felt heat when the light was most bril- 

 liant. Dumeril, in speaking of the glow-worm says, 

 " This phosphorescent light appears to be intended 

 by nature as the lamp of love the pharos the tel- 

 egraph of the night, which scintillates, and marks, 

 in the silence of darkness, the spot appointed for 

 the lover's rendezvous." The same opinion is en- 

 tertained by Kirby and Spence. They say, the torch 

 which the ringless female, doomed to crawl upon 

 the grass, lights up at the approach of night, is a 

 beacon which unerringly guides the vagrant male to 

 her love-illumined form, however obscure the place 

 of her abode. 



Whether the light emitted by the glow-worm is 

 intended for the purpose above alluded to, or not, is 

 yet but a conjecture; as De Geer says, "that this 

 insect shines in its infant state, in that of the larva, 

 and even after it has taken the form of a nymph.'' 

 Now in the first of these states it cannot propagate, 

 and still less in the second. There are several 

 authors who affirm that the male insect also emits 

 light. The first of these is Ray, who discovered it 

 in the common glow-worm, lampyris noctiluca, which 

 lias been confirmed by Geoffrey and Miiiler. The 

 light emitted by the male, however, is much fainter 

 than in the female. Illiger mentions that in two 

 foreign species the lampyris splendidula and henn- 

 ptera, the males emit a very vivid light. The glow- 

 worms have the power of regulating at pleasure the 

 degree of their light, or of obscuring it entirely. 

 Murray says that the eggs of the glow-worm are 

 luminous. White, in his Natural History of Sel- 

 bourne, says, that from personal observation he 

 conceives these insects "put out their lamps " between 

 eleven and twelve at night. Shakspeare also made 

 the same remark. 



If the glow-worm is crushed, and the hands and 

 face are rubbed with it, they exhibit a luminous 

 appearance, similar to that produced from phosphorus. 

 When a glow-worm is put into a phial, and the pliial 

 is immersed in water, a very beautiful irradiation 

 takes place. 



Fig. 34 is the common glow-worm (Lampyris 

 noctiluca}. Fig. 24 represents one of the sacs of the 

 glow-worm extracted, and very greatly magnified, in 

 order to exhibit its construction as described by 

 Macartney. 



Fig. 42 is a greatly magnified view of the inferior 

 surface of the abdomen of the lampyris lucida, after 

 the integuments have been removed. 



The great lantern-fly. (Fulgora lanternaria.') 

 This is the most vivid of all the luminous insects. 

 It affords a light so great, that travellers walking by 

 night, are said to be enabled to pursue their journey 

 with sufficient certainty, if they tie one or two of 

 them to a stick, and carry this before them in the 

 manner of a torch. It is common in many parts of 

 South America, and is described by Madame Merian, 

 in her superb work on the insects of Surinam. She 

 gives the following entertaining account of the alarm 

 into which she was thrown, by the phosphorescent 

 flashing which proceeded from them in the dark, 

 before she had been apprized of their shining nature. 

 The light emitted by this fly, proceeds entirely from 

 the hollow part of the head, which has been denom- 

 inated the lantern. 



"The Indians" says M. Merian, "once brought 

 me a number of lantern-flies, before I was aware 

 that they shone by night, which I shut up in a large 

 wooden box. In the night they made such a noise, 

 that I awoke in a fright, and ordered a light to be 

 brought, not being able to guess from whence the 



