AN OUTLINE OF BRITISH CATERPILLARS. No. I. Genus, VANESSA. IN a former Volume of The Analyst, we gave a slight notice of the new and valuable work of Messrs. Boisduval, Rambur, and Graslin, on the Caterpillars of Europe.* At the close of that Review, a promise was held out to the entomological student, that we would revert to the important subject, and occasionally present a sketch of the various Lepidoptera, in this active and interesting stage of their progress from the ovum to the adult or imago state. Such promise we shall now redeem; taking, as by far the most minute and generally correct which we have yet met with, the descriptions of the different Caterpillars from the zealous and enlightened French entomologists, to whose unrivalled work we have just adverted. In reading these descriptions, some allowance must obviously be made for the diversities of colouring which may result either from the accidental variations, occasionally exhibited by all organized productions, or from differences of food and climate. The beautiful genus, Vanessa, belonging to the Family of the Nymphalidæ of modern Entomologists, is, as regards the British species, divided, by the accurate and scientific Curtis, into three Sections, or Sub-genera; respectively characterized by the figure of the wings of the adult insects composing it, and the habits of their Caterpillars. Preferring the arrangement of Curtis to every other yet published, we shall take the liberty of almost literally transcribing it from his admirable Illustrations of the Genera of British Insects.† * See Analyst, vol. ii., p. 53. + British Entomology, vol. ii., pl. 96. All the species of the modern Lepidopterous genus, Vanessa, were comprehended, by Linnæus, in his great genus, Papilio; the principal characteristic distinction of which was the clubbed antenna. Stephens,-Systematic Catalogue of British Insects, Part ii., p. 11, has severed from the genus, as constructed by Curtis, the 7th species; and, placing it in a new genus, under the title of Cynthia Cardui, enumerated the Hampstediensis, (Hampstead-eye, of Albin),-probably a mere variety of V. cardui,—as a distinct species. In his projects of entomological innovation, rather than of reform, this distinguished author has, however, been outstripped by Professor Rennie; who, in addition to Cynthia, has formed two new genera, Comma and Ammiralis, respectively including the C. album and Atalanta, of Curtis. See Conspectus of Butterflies, etc., p. 8. The Chrysalis, or Pupa, of all the species of the genus are, it may be observed, of an angular figure; and attached, as will be seen in the accompanying wood-cut, to the various bodies from which they are suspended, by the tail.* These figures of V. antiopa, in its various states, were executed, under our own inspection, by a Birmingham artist, named Royle; and are his first attempt at the representation of entomological subjects on wood. We insert them here, as illustrating the figure of the wings characteristic of Mr. Curtis' second Sub-genus, and the general aspect of the Caterpillar and Chrysalis of the genus. For the future, any iconographical illustrations which we may give on this subject, will be either drawn from nature, or borrowed from the admirable engravings of Messrs. Boisduval, Rambur, and Graslin. Genus, VANESSA. A. Wings irregularly lobed. Caterpillars gregarious, with bituberculated heads. Species 1. Vanessa C. album, The Comma. B. Wings angulated. Caterpillars gregarious. 2. 3. 4. 5. Urtica, The Lesser Tortoise-shell. Polychloros, The Greater Tortoise-shell. c. Inferior wings rounded and indented. Caterpillars solitary. Of the Caterpillars of these seven British species, belonging to the genus Vanessa, our limits will allow us to trace only a description of the following three. In a future number, we shall present figures of the perfect insect; illustrative of the two remaining subgenera of Vanessa, and terminate our list of the caterpillars by a description of the other four. The first two of the following belong to the 2nd, and the third to the 3rd Sub-genus, as arranged by Mr. Curtis. Vanessa Urtica. Boisduval, Nymphalides, pl. 1. fig. 4, 5, and 6; —Donovan, v. ii., pl. 55. Caterpillar: blackish, minutely sprinkled with yellow. Each ring exhibiting a circular row of seven branched spines; except the 2nd and 3rd, which have but four, and the 1st and last completely destitute of them. Dorsal spines blackish, brighter at their extremity; those of the two lateral rows slightly yellow. The body exhibiting, in addition, some minute, almost imperceptible, greyish, scattered hairs. On the back, a dorsal streak of lemon-yellow, varying in breadth; more or less well defined, and divided longitudinally by a black line. On the sides, another streak, of like colour, frequently double, and enclosing the blackish, minute, and scarcely visible stigmata. Head black, slightly hollowed and rough. Inferior surface of the body yellowish-grey, or livid yellowish-green. Scaly feet black; the others greenishgrey. A ventral streak, of dark-green colour, and broken, ordinarily existing between the membranous feet. In some individuals, the yellow bands are very distinct; and the blackish interval, separating them, copiously spotted with yellow. In others, they are narrow, and faintly marked. The colour of these bands varies, also, from a fine lemon- to a greenish-yellow. This caterpillar, common throughout the greater part of Europe, lives, in societies, upon the various species of the nettle, as Urtica dioica, urens, and pilulifera. In early age, it exhibits a blackish or blackish-grey hue: assuming, after the second moult, the outline which it retains to the period of metamorphosis. These caterpillars, when upon the eve of taking on the chrysalid form, disperse; and, creeping along trees or walls, suspend themselves to undergo the wonted transformation. Sometimes, although rarely, they attach themselves to the plant on which they have previously fed. They are found from May to the end of September. The Chrysalis is ordinarily of a slight violet ash-grey, or fleshgrey colour; often marked with golden or silvery spots on its anterior part. Dorsal points conical and strongly marked. Sometimes, it is met with, under the coping of walls, completely of a splendid golden-yellow colour. In this case, however, the chrysalis has invariably been perforated by an insect of the Ichneumon, or rather of the Chalcis, tribe. The perfect insect is evolved at the expiration of from fifteen to eighteen days. Vanessa Io. Boisduval, Nymphalides, pl. i., fig. 1, 2, and 3; Donovan, vol. vi., pl. 206.—Caterpillar: deep velvet-black, punctated with white. Each ring, except the first, furnished with six longish, black spines, rather hairy than branched. The first, more slender than the rest, and destitute altogether of spines. Head, and scaly feet, of a shining-black. Membranous feet, reddish-yellow, bordering on ferrugineous. Stigmata, blackish and scarcely visible. Exists, in numerous societies, over the greater part of Europe, during July and September, upon Urtica dioica, and pilulifera, and, sometimes, upon Humulus lupulus. When going into the chrysalid state, the caterpillar quits its place of nativity, and suspends itself to the leaves of the nettle, or other adjacent plant. The Chrysalis is often of a golden-yellow, sometimes of greyish, tinted with violet, colour; and marked with silvery spots on the thorax. Somewhat more elongated, in figure, than that of V. urtica with the dorsal points more prominent; the head more dis Perfect Insect dis tinctly bifid; and the abdomen more convex. closed in eighteen days, or later, according to the peculiarity of site. Vanessa Atalanta. Boisduval, Nymphalides, pl. ii; Donovan, v. viii., pl. 260:-Caterpillar: thick, shortened; ordinarily of a dull yellowish-grey, above; with a sinuous, sulphur-yellow, lateral streak placed below the stigmata. Each ring, except the first two, bearing seven shortish, circularly ranged, yellow or reddish-yellow, branched spines: those of the more anterior rings usually blackish at the extremity. Head black, rugose, slightly hollowed out above. Body, below, yellowish-grey or blackish; membranous feet violet; the scaly feet, and stigmata, black. This caterpillar exhibits almost countless diversities of colour. The most common variety is violetblack, sprinkled with whitish points spines, pale-yellow, and slightly ferrugineous at the base. Dorsal streak, of deeper colour than ordinary: the lateral, rather broad, and pale-yellow. Below, violet-black, with paler membranous feet. At an early age, body, and most of the spines, blackish: yellow streak, broken; and superior part of first ring, sometimes yellowish. It lives, in Europe, upon Urtica dioica, urens, and pilulifera, almost solitarily and conceals itself in one or more leaves of the plant, which it unites by the aid of silken threads. Hence, difficult of discovery by persons unacquainted with its peculiar habits. The leaves of the nettle, thus sewed together, may readily be mistaken for the work of an Aranea or Botys. In a short time, having attained the full size, the Caterpillar quits its place of concealment; and attaches itself to the cornice of a wall, or the trunk of a tree, to assume the chrysalid state. Sometimes, however, it undergoes this metamorphosis within the leaf by which it has been previously sheltered. Most commonly, found from August to the commencement of October. : The Chrysalis is large, somewhat shortened in figure, and less angular than that of its congeners. Colour, grey tinged with white, or pale violet-grey, with a few golden spots. The perfect Insect is evolved in from twelve to fifteen days. Birmingham, December 12th, 1835. P. [The caterpillars of some other genus, or genera, of British Lepidoptera will be examined in our next Number.] |