FAMILY HABITS IN BUTTERFLY LARViE THE PAPILIONIDS. 29 



upper surface of a leaf of the foodplant. One suspects that the remark 

 of these authors (op. cit.), that they found the larvae of Papilio erithonius, 

 " literally in flocks," feeding on a leguminous plant with aromatic 

 leaves, does not simply mean that the larvae were in extraordinary 

 abundance, but that they were, in the strict sense, gregarious. 



The Papilionid larvae, based on their resting-habits, fall roughly 

 into three groups: (1) Those that rest quite openly, and whose general 

 coloration and appearance make the larva resemble a bird's-dropping, 

 or something quite different from a lepidopterous larva, especially 

 when young. (2) Those that cling closely to a certain part of their 

 foodplant, and whose shape, colour, and general appearance bring 

 them into close protective resemblance with their immediate surround- 

 ings. (3) Those that rest openly and exposed, their brilliant colours 

 in general harmony with their surroundings, but yet are generally 

 assumed to gain protection less from cryptic effects resulting from 

 their resting-position, than from other causes, objectionable taste, 

 smell, etc., to which their bright colours are assumed to act as a guide, 

 the latter, consequently, being usually designated " warning colours," 

 though their efficacy is, in most cases, very problematical. 



We have already discussed the resting-position with regard to the 

 larval coloration and its possible cryptic value or the reverse, in the 

 Papilionid larvae (antea, vol. viii., pp. 67-72), and, except incidentally, 

 it does not appear to be at all necessary to cover the same ground 

 again, although, in dealing with this chapter, students should certainly 

 refer to what is there written. Buckler observes that the usual 

 attitude of the larva of Papilio machaon, in repose, is, from the very 

 first, much like that of a Sphinx, with the neck arched and the head 

 bent down, but Floersheim notes (Ent. Piec, xxi., p. 14) that, although, 

 when very young, the larva of this species rests thus, with its fore- 

 segments raised and arched, giving the appearance of a miniature sea- 

 horse (a position particularly adopted when undergoing ecdysis), it 

 also more frequently rests with the foresegments very slightly raised 

 and not arched, the young larva holding itself to its pabulum by means 

 of the last three pairs of prolegs or anal claspers, keeping its thoracic 

 legs tightly shut, and that this position is the one usually taken when 

 the larva is merely at rest after feeding. Generally it rests with its 

 head towards the base of the leaf, but always on the upperside, and, 

 even in heavy rain, the young larvae will not retreat to the underside 

 of the leaves ; as it gets older it still keeps to the upperside of the leaf, 

 usually near the midrib, but, as it nears maturity, loses the habit of 

 resting with the head towards the base, and turns its head towards the 

 apex of the leaf, and does so almost entirely when fullfed, although, at 

 this time, it also sometimes rests on the stems of young shoots, upon 

 the leaves of which it has been feeding. When young, the larva 

 seems to rely for protection almost entirely on cryptic effects, but 

 warning when discovered. The young larva, black with a white 

 saddle, imitates a bird's-dropping ; later it becomes light green with 

 black bands and orange spots, and away from its food looks con- 

 spicuous enough, but, on its foodplant, especially among the flower- 

 heads, is not at all easy to see. Floersheim thinks that the appear- 

 ance of the " bird's-dropping " stage may serve a double purpose, as, 

 when feeding on the seed-pods of Dictamnus, the larvae are much paler 

 in colour, and closely resemble the light brown-green colour of the 



