European butterflies and moths : based upon Berge's "Schmetterlingsbuch" / based upon Berge's "Schmetterlingsbuch" by W.F. Kirby.

  • Kirby, W. F. (William Forsell), 1844-1912.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: European butterflies and moths : based upon Berge's "Schmetterlingsbuch" / based upon Berge's "Schmetterlingsbuch" by W.F. Kirby. Source: Wellcome Collection.

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    rNTR OD UCTICN. Xlll each segment, except the first, third, fourth, and last, is provided with a small opening on each side, above the feet, which is surrounded with a horny margin, and through which the larva breathes. These air-holes are the spiracles, already mentioned, and are often placed on round coloured spots called stigmata. The spiracles placed on the second and twelfth segments are generally larger than the others. The larvae of the typical Papilionidcz have a fleshy retractile fork on the second segment. Every Lepidopterous larva has a pair of legs {pedes) on each of the three thoracic segments. These consist of three cylindrical joints, covered by a more or less horny skin, and are terminated by a claw. They are thickest at the base, and taper towards the extremities. These are the true legs, which correspond to those of the perfect insect ;* and in the larva of the Lobster Moth {Stauropus Fagi, PI. 30, Fig. 8, d) they are of extraordinary length. In addition to these, most larv^ are furnished with four pairs of false legs, or “prolegs,” on the seventh to the tenth segments ; and another pair called “ claspers,” which terminate the last segment. These prolegs consist of two fleshy joints, and their extremities are either rough, very movable, and adapted for climbing, and fur- nished on the outer side with hooks directed inwards {pedes semi-coronati); or else they are smooth, shaped like a bolster, and not adapted for grasping any object, but furnished with a continuous or nearly continuous circle of small hooks, directed outwards {pedes coronati). Legs constructed for climbing are only met with among the larvae of Macro-Lepidoptera ; but some of these have legs of the other description. This is especially the case with those which feed in the interior of plants, or in cases. None of the larvae of Mia'o-Lepidoptera have climbing legs. Several larvs belonging to the families Notodontidce and Drepaniclidce have no claspers, because the terminal segment ends, in the former, in two long slender processes (as in the larva of the Puss Moth, PI. 30, Fig. 4, d); and in the latter, it terminates in a point. The larvae of the Geometrce have generally only one pair of prolegs on the tenth segment (Looper Caterpillars, like that of Ennomos Alniaria, PI. 43, Fig. 2, a), but in some genera we find a pair on the ninth segment also (as in the larva of the Light Emerald Moth, PL 43, Fig. i, a)] while in the larvae of several genera of Noctuce, the prolegs are wanting, or rudimentary on the seventh, and sometimes also on the eighth segment, as may be seen in the larva of Agrophila Stdphuralis (PI. 42, Fig. 3, a). The larvae of these aberrant NoctiuB are called “ half-loopers.” In other larvae the front prolegs are smaller and less fully developed than the hind ones. The larvae of the Psychidcz, which live in cases, and the tortoise-shaped larvae of the Cocliopodidce, are indeed furnished with prolegs, but these are all very short. Those larvae which are provided with the full number of legs crawl along. Those of the Macro-Lepidoptera creep slowly, but the movements of the larvae of the Micro-Lepidoptera are generally very rapid ; and the latter can run backwards as well as forwards. Looper larvae have a very peculiar mode of walking ; they fix themselves firmly by their true legs, and then draw the prolegs and claspers up to them by strongly arching their body. They then attach themselves by their prolegs and claspers, stretch out their body, and fix themselves as before with their true legs. The motion of the half-loopers is more crawling, but they likewise arch their bodies in the middle, more or less, when walking. Many larvae exhibit other structural peculiarities. These consist chiefly of fleshy excrescences or appendages, which may occur on the middle line of the back, or in pairs, or in a regular series ; * The thoracic legs are absent in the larvce of the genus NepHcula (which contains the smallest of all known moths), which are furnished instead with nine pairs of undeveloped prolegs, wdthout claw.=, on segments 3 to ll ; as well as in the entirely footless larva of Gelechia Inopella, which lives in the seeds of the common Flea-bane {Inula dysenterica)-, and also in the footless larvK of the genus Parasia, which live in the heads of different composite plants. d^