FAMILY HABITS IN BUTTERFLY LARV^ THE PAPILIONIDS. 33 



suggests that the panting, spasmodic approach of so singular-looking 

 an object may be a source of fright, or possibly of curiosity, to some of 

 its natural enemies, and sufficient to protect it till it again gains cover. 

 Edwards says (Can. Ent., xiii., p. 13) that the larvae of Laertias 

 philenor are far more active than those of any other Papilionid species, 

 and can travel with great rapidity. Scudder adds (Butts. New Engl., 

 p. 1249) that the front filaments of the larva are freely movable, and 

 that, when travelling, the caterpillars keep them in constant motion up 

 and down, generally alternating through an angle of about 25°, in the 

 downward movement not quite reaching the surface on which they are 

 walking; Scudder also observes that, during their fourth stage, the 

 larvae have a curious habit of tapping on the leaf repeatedly, though 

 not rapidly, with the anterior pair of legs, not simultaneously, but one 

 at a time. Floersheim also notes (Ent. liec, xxi., pp. 147-148) that 

 the larva of this species is exceedingly active after its middle stadium, 

 noting that it will often crawl a distance of 200 or 300 yards in order 

 to find asuitable place for pupation, and adds that, like the larva of 

 Papilio machaon, but unlike that of Tphiclides ajax, the larva always moves 

 forwards, and will turn completely round rather than go backwards. 

 He confirms Scudder's account of the peculiar habit that the adult 

 larva (in its fourth and fifth stages) has of drumming with its thoracic 

 legs on leaves, both when feeding or half-resting ; he has also seen it 

 do so on the backs of its companions. Of the newly-hatched larva of 

 I. aja.v, Floersheim also notes (op. cit., p. 114) that it is very active, 

 crawling about the stem and leaves of papaw readily, and letting itself 

 down by a silken thread if disturbed or frightened; when older it loses 

 the habit of descending by means of a silken thread, but remains rapid 

 in its movement till the end. It, however, will only display its 

 activity if disturbed or in search of food. 



The silk-spinning habit of the Papilionid larvae is closely allied to 

 the usual sluggishness of habit, the silk being often spun as a means 

 of security of foothold ; thus, Fitch says that, as the larva of Papilio 

 polygenes walks along the slender pedicels of an umbel of its foodplant, 

 it moves its head first to one side and then to the other of the stem, 

 attaching a slender thread of silk which it spins from its mouth to the 

 stem to form a more secure foothold. Mathew notes (Tram. Ent. Soc. 

 Lond., 1888, p. 173) that the orange-feeding larva of Papilio erectJieus 

 spins silk on the orange leaves to obtain a more secure foothold. 

 Buckler notes (Larvae Brit. Butts., p. 2) that the larva of P. machaon 

 also spins silk for a foothold, but Floersheim says (Ent. B,ec, xxi., 

 p. 16) that the quantity of silk spun by this species varies with the 

 foodplant, that, on Ptelea — a tree — the young larvae spin noticeably 

 more silk than when feeding on the lower-growing Skimivia bushes, 

 whilst on fennel-plants the larvae seem to spin no silk at all, perhaps, 

 he adds, because the slender and rounded leaves of the fennel afford a 

 sufficiently secure position without having to attach themselves to 

 anything else. Scudder says that the silk-spinning habit is well- 

 developed in Laertias philenor, and that, without its support, its heavy 

 weight would prevent it from obtaining a firm hold, but Floersheim 

 (Ent. Rec, xxi., p. 14b) has only observed it to spin silk when about to 

 undergo ecdysis, and then it does so freely. The same observer also notes 

 (oj). cit., p. 114) that, with the exception of letting itself down with a 

 silken thread when recently hatched, the larva of Ip/ii elides ajax makes 



