made to exterminate them. Whether this is due to the greater number of the young lice proving to be males or from the effects of parasites remains to be determined.1

Wings membraneous, hyaline, dotted with short points extending outward, sending out at the base a forked line, one toward the upper, and one toward the lower margin. Mons. V. Signoret says in his essay on Lecanides, that in the place of the lower wings of the male there are two halters or balancers, which I have been unable to discover in the mounted specimens before me, although it is quite possible that they may be found in fresh specimens. The females continue absorbing nourishment during the remainder of the summer and return to the limbs at the approach of frost in the autumn. In Fig. 1, Mr. Riley has illustrated the egg-mass as occurring upon the leaf, which is contrary to my experience in Illinois and Iowa, although were the season longer it might be the case, and thus become doublebrooded since it is well known that the varied temperature has great effect upon the length of time insects remain in their several stages.

Three kinds of Lady-birds (Coccinelida), are found more or less numerous upon the infested trees destroying the acericorticis during the summer months. The Hyperaspis signata Olivier is perhaps the most abundant and valuable. The larva is small, light colored, and covered with a peculiar white downy substance. They are found inside the waxy mass devouring the eggs, and through their assistance many are thus destroyed before hatching. The outside of the egg-mass appears entire, but by carefully separating it, the larva can be observed, in the act of devouring the contents of the egg, by the aid of a common lens. Only one larva is found in each egg-mass. When fully grown and about to change to the pupa state, they emerge and attach themselves to the tree. The imago is a small black beetle with one bright red spot on each elytra.

The Chilocorus bivulnerus Muls. (Fig. 5), although not found in such numbers as the signata are equally as important since they

1 Lecanium acericorticis male, see Fig. 4. Color fuliginous, with the thoracic segments darker than the remainder of the body. Head small, angular in front, and at the sides. Antennæ 10-jointed, filiform, pubescent, fourth, fifth and sixth longest. Color light brown. There are two ocelli between the antennæ. Thorax large, the mesothoracic band distinct, shiny, the metathorax forming an arched shield extending a short distance over the abdomen. Legs stout, sparsely covered with hairs, tarsi furnished with two claws at the end. Abdomen ends in a tubercle which protects the penis, the entire nearly half as long as abdomen.

destroy the young lice. The larvæ are readily recognized from the larvæ of the former by being covered with a large number of black spines, they are considerably larger, and are not found inside the egg-mass. They are ravenous feeders, and require a great number of lice be

fore they complete their larval state. The imago resembles the signata in color, but is much larger and equally voracious with the young.

The Anatis 15-punctata is also beneficial in its destruction of the acericorticis, and is larger even than the preceding ones, but does not occur so plentifully.

The larvæ are furnished with six rows of stout spinulated spines along the body, the upper surface of which is black, while beneath it is pale, and is nearly half an inch in length. The beetle is black on the head and prothorax, having seven black spots on the brownish-red elytra, and a black spot on the scutellum; it is seven-twentieths of an inch in length.

The larvæ of a species of Chrysopa are found assisting in the work of destroying the enemy, but not in any considerable numbers, as also two species of Reduvida and one Acarus.

The females are destroyed by means of a parasite which live upon the fatty substance with

out disturbing the vital organs, and only destroys the insect when changing to the pupa state inside the body of the other from which it emerges through a cylindrical hole on the dorsal side. This parasite is double-brooded, the second

brood appearing the middle FIG. 6.-Coccophagus lecanii nov. sp. of August. The insect be- ", pupa; b, imago; hair lines natural size. longs to the genus Coccophagus, thanks to Mr. E. T. Cresson for its determination, and appears to be undescribed (figure 6).1

Coccophagus lecanii, nov. sp. Fig. 6. Body elliptical oval; color cinereous. Head as broad as the thorax, smoky brown in color, and pubescent. Antennæ eight-jointed, first joint longest. Thorax nearly black, with a crescent-shaped spot of pale yellow placed crosswise upon the hind part of the thorax. Abdomen elliptical, a little longer than the thorax. Legs light brown with the femora darker, hairy, furnished at the apex of tibiæ with a spur; tarsi five-jointed, first joint longest.

Wings membraneous, hyaline, ciliated. Fo e wings with the rib vein running parallel with the margin nearly one-half its length, where it unites and ends in a stigma somewhat beyond the middle. The lower wings smaller, without veins, the hairs forming a fringe on the lower side.

THE FIRE-FLIES AND THEIR PHOSPHORESCENT

THE

PHENOMENA.

BY MRS. V. O. KING.

most interesting feature distinguishing these insects is their phosphorescent qualities. Light, so universal in its influences upon the life processes, and made familiar to us through the multiform media of its evolution, is known to result from a combustion of dead matter. To this known fact, Lampyris, creeping and flying, and at the same time emitting light, would seem to present a contradiction.

This singular fact early attracted the attention of naturalists and philosophers. A traveler in Japan, about the middle of the 15th century, studied its phenomena, discovering two kinds of light; and later, Mr. McCartney, by anatomical investigation, found two vesicles from which he supposed the more permanent light to proceed. Similar discoveries were made about the same time by a Polish naturalist. Many distinguished entomologists have given attention to the subject; even Arago studied the character of the light in connection with that of the sun, and found it to exhibit the same species of refrangibility with the light of that body.1

Matteucci, who studied this phenomenon from a chemical standpoint, concluded that there was positively no phosphorus present in the luminous segments, and therefore accounted for the manifestation by other means.

Prof. Pancerri of Naples, a few years since, concluded that phosphorescence in animals is the result of oxidation of certain fatty material, composed partly of epithelial cells in a state of partial decomposition, a manifestation (as Draper also says) of dead matter only; due to a slow combustion by which vibrations are excited capable of transmitting luminous rays. This phosphorescent substance, Pancerri finds secreted in glands in all cases except noctulica.

1 The spectrum given by the light of the common fire-fly of New Hampshire (Photinus ?) was found by Prof. C. A. Young to be perfectly continuous, without trace of lines either bright or dark. It extends from a little above Fraunhofer's line C in the scarlet, to about F in the blue, gradually fading out at the extremities. This portion is composed of rays which, while they more powerfully than any others affect the organs of vision, produce hardly any thermal or actinic effect; in other words, very little of the energy expended in the flash of the fire-fly is wasted. Prof. C. A. Young in the AMERICAN NATURALIST, Vol. iii, p. 615.—EDITORS.

I have examined many of the Lampyrida; the phosphorescent segments in the highly organized species contain a translucent substance resembling half-cooked starch, situated just behind a yellow waxy-looking membrane. This membrane has, on its ventral aspect four distinct spiracles for the admission of air.

Through these spiracles and contiguous parts may be seen at times quick brilliant flashes of light, made more rapid and vivid when the insect is handled, and followed in its normal state by a milder emanation, which may be compared to the embers of the previous conflagration. This second light is yellowish and dies out slowly. The first appearance of fire-flies in the twilight is indicated by a red, followed shortly by yellow, and later by the characteristic green light.

Different species vary in the degree of activity and also somewhat in the manner of emission. The phenomenon is also subject to changes during the metamorphic period.

The larva in Photinus emits a steady green light from the posterior segments on the ventral surface. The pupa light, at first green, soon assumes a whiter less brilliant character, diffused over the entire body.

The imago of the apterous female of Pleotomus exhibits greater intensity, and over a larger surface than in male forms, but steady, and at times disappearing from the posterior segments to be diffused as a white light over the body. This insect is scarcely more than an egg-bag, and its light is never so green as in other species. There is almost as great a diversity of degree and manner as of varieties, each enabling the observer to identify them at night.

A peculiar odor is perceptible, at times, in fire-flies. An English writer first noticed this, but afterwards concluded that he might have been mistaken.

The soil which is most frequented by glow-worm larvæ consists largely of decomposed rocks, and produces a growth whose ash is intensely sulphurous to the taste. In these places may also be found earth-worms filled with phosphorescent matter, and snails, the favorite food of the glow-worm larvæ, while the Primula mexicana, the vegetable diet of adult winged species, also abounds. All these features obtain in a moist soil and open air of fields, where, according to Ebermeyer, ozone is found in greatest quantities, and oxygen its other form.

A calcium sulphuret of phosphorus, prepared by heating sulphur with calcined oyster shells, is said to give out a yellow light when exposed to the sun's rays, but under decomposed light there is a change to green. The decomposition of certain rocks furnishes phosphates of calcium to the soil, whence having been appropriated by plants it eventually supplies animals. When not oxidized in the stomach it is supposed to be absorbed into the system in certain oils. Phosphorus in its active state ignites spontaneously in contact with the air.

In Lampyris we see changes identical with those presented by a calcium sulphuret of phosphorus from the red or yellow to green. The emission of the greatest amount of light would also point to the presence of phosphorus, this occurring most freely in the open air, and when the insect is either flying or excited, when the body is presumed to be most fully inflated with air, the spiracles on the luminous segments being very favorable for its admission.

The second light, referred to as of a milder kind and with a steadier emanation, would seem to be portions absorbed by the translucent substance during the more active evolution of light, and reflected from the less permeable inner face of the dorsum until exhausted.

The uses of the light of Lampyris seem as doubtful as its nature. As it cannot be of service in the larval state either for sexual attraction or to secure food, its presence at this early period must be for the benefit of succeeding stages, and especially for the imago in the case of the apterous female.

The periodicity of the phenomenon may be ascribed to that property of the ganglia which enables them to give a periodical exhibition of an original disturbing cause.

There is a definite relation between the proportion of light emitted, and the color of the enclosing membrane which indicates the former's bleaching power.

Draper illustrating a truth says, that "not a shadow falls for an instant upon a wall but it leaves an ineffaceable stain," thus by his shadows bringing the power of light into bold relief. If a ray of light falls, however softly and but for an instant, upon an object, we may presume that a change, whether by chemical or mechanical means, ensues. Flowers and fruits by their irregular surfaces break the sunshine into specific hues, thus acting as shadows to themselves. Animals also respond in coloring to the influence of light.