28 BRITISH BUTTERFLIES. 



machaon; the spiders, he adds, would even attack almost full-grown 

 larvae, which soon died and turned black after being bitten. Writing 

 of the larvae of Laertias philenor, the same observer notes (Ent. Rec, 

 xxi., p. 148) that he has kept them in large quantities out-of-doors in 

 a kitchen-garden, full of insectivorous birds, but has never seen 

 either a larva or a pupa attacked by one. Mice will eat the pupa?, but 

 even in winter the birds refuse them. The ichneumon -fly which infests 

 the larvae of Papilio macliaon, he says, never stings those of Laertias 

 philenor, and, out of all the pupae which he has received from America, 

 he has never found one containing Tror/as exesorius, the pest of the 

 Nearctic Papilionids. He has seen wasps hover round the halfgrown 

 larvae, but never seen these attacked by them. 



Although one may find as many as 80 or 40 young larvae of Papilio 

 macliaon on a single plant of Pencedanum palnstre on Wicken Fen, yet 

 each larva is found to be living singly and independently, and to show 

 no gregarious tendencies, and the larvae of the Papilionids generally 

 appear to be solitary in their habits. A few exceptional instances, 

 however, have been recorded, and Scudder notes (Butts. New Engl., i., 

 p. 1223) that, in one South American group, the caterpillars live on 

 plants belonging to the Aurantiaceae, in societies of one or two hundred 

 individuals, and, when young, feed side by side in rows, whilst the 

 larvae of one Nearctic species, Laertias philenor, are strictly gregarious 

 in early life, and semigregarious afterwards, distributing themselves 

 when fullgrown over the foliage of the Aristoloc/tia, on which they 

 feed. Edwards describes in detail (Can. Ent., xiii., p. 13) how the 

 newly-hatched larvae of this species betake themselves to the edge of 

 a leaf, and, ranging themselves at right angles to this, side by side, feed 

 after the manner of large Botnbycidae, that this habit continues till they 

 are halfgrown, when they separate; Scudder observes (Butts. New Eng- 

 land, p. 1249) that one he separated rested on the underside of a leaf, but 

 that, as soon as a companion was provided, they at once travelled from 

 the upperside, where they were placed, to the underside, and remained 

 there, resting side by side. Floersheim observes (Ent. Rec, xxi., pp. 

 146-7) that the young larvae feed on all occasions on the underside of 

 the leaf, and are gregarious, each batch of eggs splitting up as a rule 

 into two companies of larva? ; whilst feeding, the larvae touch one 

 another, so that, if one of them moves, it sets the others in motion by 

 the imparted shock, and if one extrudes its osmaterium the rest follow 

 suit ; a little later they rest in small companies, usually of ten to 

 fifteen on the underside of a leaf of Aristoloc/tia ranged in files like 

 bands of soldiers, with heads pointing indifferently inwards to stem or 

 outwards to tip of leaf; when two-thirds grown the larvae are still 

 gregarious, though less so than in the earlier stages, and rest usually, 

 but not invariably, on the underside of the leaves, whilst, when full- 

 grown, the larvae, though still exceedingly sociable, are not strictly 

 gregarious, and are often to be seen feeding upon the stems of the young 

 growth of Aristolochia sipho, or sunning themselves on the topmost 

 stems of the foodplants in companies of two and three, where they be- 

 come most conspicuous objects. Davidson and Aitken, writing of the 

 " Erithonius group " of Papilionids in India (Journ. Bomb. Nat. Hist. 

 Soc, v., pp. 307 et seq.), observe that the larvae of Papilio Horn e don 

 feed on Acromjchia laurifolia, that they are quite gregarious, dispersing 

 occasionally to feed, but always returning to rest side by side on the 



