HONEY-PRODUCING CATERPILLARS.

L

ATE in June, growing abundantly in the edges of woods throughout this region, may be seen the Cimicifuga racemosa of botanists, popularly called Rattleweed, or Black Snakeroot. It sends up a stalk, sometimes branching, four or five feet, terminating in a spike or spikes, six to ten inches long, of round, greenish-white buds, which stand upon short stems, and are arranged in rows about the stalk, diminishing in size till they reach the pointed top. The lower buds, when they are about the size of an ordinary pea, open first, and the flowering proceeds by degrees up the spike, so that buds are to be met with throughout a period of from four to six weeks. The flowers emit an intensely sweet odor, which renders them attractive to butterflies and bees.

But should you examine these buds with care, you will find a number of small caterpillars, the larva of the beautiful Azure Butterfly, called Lycana pseudargiolus, feeding thereon. During its younger stages it is white, and so near the color of these buds that it is well protected, and very difficult to find. Later on, it may be white or greenish, and often diversified with a few black or brown patches, irregularly diffused over the surface.

When mature the larva is one-half of an inch in length, and, like all Lycænid larvæ, is onisciform, or shaped like the little pill-bug, so common under stones and logs. The head is very small, and is placed on the end of a long, green neck, which at the junction is of the thickness of the head, but gradually enlarges, and seems to be fixed at the hinder part

of the second segment, the latter being hollowed out so as to form for it a sheath. In the final larval stages this segment is elevated, transversely compressed, and inclines forward, thereby shielding the head as the larva moves about. When quiescent the neck and head are wholly retracted, and as the former, when fully extended, is very much longer than the depth of the second segment, it must possess considerable elasticity.

The larva feeds on the heart of the bud, and to reach this cuts away the surface on one side till an opening is made sufficiently large to admit its head; and as it feeds the second segment is firmly pressed against the bud so as to permit the utmost elongation of the neck. Thus it is enabled to eat out the contents of the bud, and only desists when there remains but the empty shell. When so engaged the anterior segments are curved up and the others rest upon the stalk of the plant, but very small larvæ repose wholly in the bud. Not a single instance has been observed where an open flower has been attacked, but the destruction of buds is very extensive.

But now comes the most remarkable part of the larval hisory of Pseudargiolus. The whole upper part of the larva is covered with small, glassy, star-shaped processes, scarcely raised above the surrounding surface, from the centre of which spring short, filamentous bodies, bristling with featherylooking tentacles, which the caterpillar has the power of protruding at will. It throws them out like the tentacles of Papilio or the horns of snails. More singular still is an opening upon the eleventh segment, placed transversely and surrounded by a raised cushion, about which the granulations that cover the body of the caterpillar are particularly dense. From the middle of this opening, which is shaped like a button-hole, issues, at the caterpillar's will, a sort of transparent, hemispherical vesicle, from which is emitted a good-sized drop of fluid, which the animal is capable of reproducing when absorbed.

PSEUDARGIOLUS BUTTERFLY.

Larva Feeding on Bud of Black Snakeroot, and Guarded by Ants.

Four species of ants may be seen attending, not the small larvæ, but those that have attained the nearly mature condition. They are invariably found on or near the larva. Their actions, as they run over the body, caressing with antennæ, evidently persuading the larva to emit a drop of the fluid, are alike curious and interesting. Most of this caressing is done about the anterior segments, and while the ants are thus occupied, or rather, while they are absent from the last segments, the tubes of the twelfth seem expanded to their full extent, and so remain, without retracting or throbbing, until the ants come hurrying along with great excitement and set foot or antenna directly on or close by the tubes,

when they are instantly withdrawn. The ants pay no heed to the tubes. They seek for nothing from them, and expect nothing. But they turn at once to the eleventh, caress the back of that segment, and, putting their mouths to its opening, exhibit an eager desire and expectancy. Suddenly a dull green, fleshy, mammilloid organ protrudes, and from the summit of which comes a tiny drop of clear green fluid, which the ants, some two or three perhaps standing about it, lap greedily up. As the drop disappears, this organ sinks in at the apex, and is so withdrawn. The ants then run about, some in quest of other larvæ upon the same stem, some with no definite object, but presently return and pursue the caressings as before. The intervals between the appearance of the globule vary with the condition of the larva. Where exhaustion by long-continued solicitings occurs, some minutes elapse before renewal is effected, the tubes in the meantime remaining concealed. Fresh larvæ, however, require little or no urging, and globule follows globule, as many as six emissions in seventy-five seconds, without even a retracting of the organ. Often the presence of the ant, when the larva is aware of it, evokes, all unsought, the sugary fluid.

Ordinarily the tubes expand when the ants are absent from the last segments, and are certainly withdrawn when they come near. These tubes, from all appearances, serve as signals to the ants. When the latter discover them expanded, they know that a refection is ready, and rush to the opening in the eleventh segment where it is to be found. The tubes certainly serve no other purpose. No visible duct appears in the dome of the tube when largely magnified, and the ants seek nothing from it or the twelfth segment. They cannot be used to intimidate, or to frighten away enemies, for in the younger stages, when the larvæ have the most to dread, neither the tube nor the organ in the eleventh segment is available. The outward openings, and the orifice in the eleventh segment, exist in the youngest larval stages, but are functionless until the larva has nearly attained maturity.

Ants seldom attempt to caress or solicit young larvæ, but pass them by with indifference, seemingly knowing that they cannot emit the secretion. When an ant approaches one of these immature larvæ, the larva manifests considerable annoyance, throwing up the hinder segments, as though the ant was an enemy which it was desirous to get rid of. If the tubes could now be thrust out, the ant would be attracted, rather than repelled.

But when the period arrives that the tubes are free, and the secretion is ready to be ejected, which is perhaps just after the third skin-moulting, and it cannot be earlier, the larva grows now quiet and submissive, inviting the attentions of the ants, and rewarding their antennal caresses.

Four species of parasites affect these larvæ. Two are dipterous. These, which are of the size of the common housefly, deposit their eggs, during the second larval stage, on the back, and near the junction of the second and third segments. In process of time the grubs hatch and eat their way into the larva, to emerge when the latter has become fully grown, thus destroying its life. Another of these enemies is a minute hymenopterous insect, whose egg is placed in the very young larva, probably in the first stage of its life. The grub, in this case, eats its way out of the half-grown larva, spins a silken cocoon, from which in a few days issues the newly-matured parasite. The destruction of larvæ by these, and very likely by other similar parasites, is doubtless immense. But no parasite attacks, it does seem, the mature larva, for, if it did, the grub of the former would live within and destroy the chrysalis, and instead of a butterfly emerging therefrom would come forth the parasite. Multitudes of chrysalids of other species of butterflies are thus destroyed, but Pseudargiolus, at this stage, appears to enjoy a singular immunity from enemies.

Why this species, and doubtless many others of its family, are thus favored, will soon be apparent. Ants may be seen wherever these larvæ may be found, ever ready to receive