rxTRODUcricx. xili 



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 

 {Stanropiis Fagi, PI. 30, Fig. 8, a) they are of extraordinary length. In addition to these, most larvae 

 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 setiii-eoroiiati); 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-Lcpidoptcra ; 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 larva; o{ liliero-Lcpidoptera have climbing legs. Several larvae belonging 

 to the families Notodontidie and Drepamilidee 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 GeoinctreB have generally only one pair of prolegs on the tenth segment 

 (Looper Caterpillars, like that of Ennouios 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 larv^ of several genera of Noetitee, the prolegs are wanting, or rudimentary on the seventh, 

 and sometimes also on the eighth segment, as may be seen in the larva of Agropliila Siilphnralis 

 (PI. 42, Fig. 3, a). The larvae of these aberrant Noctuee are called " half-loopers." In other larva; 

 the front prolegs are smaller and less fully developed than the hind ones. The larvae of the 

 Psychida, 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. Tliosc of the Alaero-Lepidoptera creep slowly, but the movements of the 

 larvje of the Lliero-Lepidoptera are generally very rapid ; and the latter can run backwards as well 

 as forwards. 



Looper larvre 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 fi.x 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 larva? of the genus A^epiicula (which contains the smallest of all known moths), which are 

 furnished instead with nine pairs of undeveloped prolegs, without claws, on segments 3 to 1 1 ; as well .as in the entirely footless 

 larva of Gelechia Tiw/>L-//a, which lives in the seeds of the common Flea-bane (Inula dysentcrica]; and also in the footless larva; of 

 the genus Parasia, which live in the heads of different composite plants. 

 d^ 



