Page:The American Cyclopædia (1879) Volume VIII.djvu/48

 GLOWWORM four bright j>ointa, two on the antepenultimate abdominal segment, and two on the next pos- The L. Italiea is next in size, and is
 * lu-rn Europe, as the first is in the

niirtlii-rn i-ountries; the color is black, with thorax and legs; both sexes are winged,
 * iinl iniii-h resemble each other, the apterous

. s spoken of by some entomologists being the larva). The L. splendidula is common in Germany; the male is winged, brown gray, with a bright glassy spot on the convex mar- gin of the prothorax ; the female, whitish yel-, ith a brown spot on the centre of the prothorax, has no wings, and very short oval elytra; the luminous spots are two transverse bands on the lower surface of the two penulti- mate abdominal segments, and in the female the whole abdomen diffuses a weak light L. hemiptera, a southern species, and the small- est one third of an inch long, is opaque black, liirhu-r in the female, the posterior ventral being whitish; the males have truncated t-lvtr.-i, the females none; the light is diffused iV'-in two round spots on the penultimate seg- ment; the larvae are probably luminous, as those of the preceding species were found to be by Bunneister. The first three species conceal Glowworm (Latnpyria noctilnca). themselves in the daytime and appear at night, the males flying about in the warm summer evenings, while the females betray their situa- tions by their tranquil light among the shrubs- the last species creeps also by day, especially in damp weather, appearing toward the end of April ; the third species occurs about the end f May and the beginning of June, while the first is found most abundantly toward the end of summer. The light is greenish or more commonly bluish white, intermittent or contin- uous at the will of the insect, extinguished in of danger, and increased by active motion sexual excitement, or artificial heat; it may ntmue some hours after death, and when t maj be reproduced by warm water ; pois- is gases destroy the li-rl.t with life, while gen increases its brilliancy ; electricity pro- mt no affect on the light, while galvanism or reproduces it in dead insects. The emipches of Kfllliker and others show that at theshinmg spots is a whitish, transparent, fatty IM, Permeated by very numerous trachea; this Hill 8 h,ne wh,n r,m,,ved from the body, W MS Water f u r a long time ' and its pS rubbed up., n the fingers display a light resembling that from phosphorized mixtures. The eggs of the glowworm, the larvae, and the nymphs, are luminous; the eggs are hatched after a few weeks, and the larvae resemble the perfect females, having a body of twelve seg- ments, the first three of which bear each a pair of feet ; the head is small, and, like the caudal segments, retractile; they thrive well in captivity when kept in moist earth or herb- age, and supplied with slugs and snails, which they kill with their arched and sharp-pointed jaws, and eagerly devour ; about a week is oc- cupied in assuming the state of nymph, and in about eight days longer they appear as perfect insects. The nymph is larger than the larva, but not quite so long ; the color is at first pale yellow, with two reddish spots on the posterior part of the thorax and the segments, but the dull color of the perfect insect is visible toward the end of the nymph state; the larval jaws disappear, and the antennae are seen to have eleven joints, and the tarsi five; the last ab- dominal rings are very brilliant, and indeed the whole body seems phosphorescent. Ac- cording to Dufour, the alimentary canal of the perfect female is twice as long as the body, and the oesophagus exceedingly short, immediately dilating into a short crop. The substance from which the luminous property is derived has been often made the subject of experiment, but as yet, according to Matteucci, without the de- tection of any phosphorus in it, though the cir- cumstances attending the light resemble the being increased by warmth, diminished by cold, and destroyed by irrespirable gases, oil, alco- hol, acids, and strong saline solutions; these phenomena admit of a better explanation on Matteucci's theory. This author, in his Lecons sur les phenomenes physiques des corps vivants, explains all cases of animal phosphorescence on physico-chemical principles. From his experi- ments we know that the light of the glowworm may cease before the death of the animal, or may be considerably prolonged after this event; that the light is without heat, as far as our rude instruments can detect ; that it ceases soonest in carbonic acid, and in hydrogen in from 30 to 40 minutes ; that it is increased in oxygen, and .asts three times as long as in other gases, both for parts and for the entire insect; that it consumes a portion of oxygen, which is re- placed by carbonic acid, and is therefore the vrpduct of. a true combustion ; that when not hinmg, and in contact with oxygen, none of -his gas is taken up, and no carbonic acid is orrned; that heat to a certain extent increases, while cold diminishes its brightness; that when e luminous substance has been altered by too great heat or the action of gases so as to lose its phosphorescence, this .property cannot be >v. stabhshed; finally, that carbon and not phos- i r ?i S '? ?, ne f the elemei >ts of this substance, that the phosphorescence is produced by the combination of the carbon with the oxygen The luminous matter from the living insect,