36 BRITISH BUTTERFLIES. 



Aitken); in Thursday Island, P. indicatus ; in Australia, P. erectheus 

 and P. anactus (Mathew), etc. 



It has been before noted how the larva? of P. machaon eats " rue " 

 with avidity, and that the American P. polygenes takes readily to the 

 introduced Dictamnus fraxinella ; it is to be noted that Davidson and 

 Aitken observe (Ann. Bomb. Nat. Hist. Sue, v., pp. 366 et seq.) that the 

 larva of P. erithonius, one of the commonest Bombay species, whose 

 usual food is lime and orange, forsakes these for the unpleasantly 

 odoriferous garden -rue. It is to be noted that many authorities now 

 refer the orange, lime, etc. (the old Auraniiaceae) to the Rutaceae, to 

 which rue, skimmia, and dittany belong. 



Of the feeding-habits of the Papilionid larvae, various scattered 

 details have been published, which are, however, difficult to summarise. 

 The newly-hatched larva of Papilio machaon eats its eggshell very 

 completely, that of Laertias philenor partly, whilst that of Iphielides 

 ajax appears (contrary to Scudder's statement) only to eat a hole 

 sufficiently large to escape from, so that there is no uniformity in 

 habit throughout the superfamily, although there may be in the 

 separate groups. Similarly, the young larva of Papilio machaon always 

 eats its cast skin, and continues to do so all its life, that of Laertias 

 philenor often, but not necessarily always, does so, whilst that of 

 Iphielides ajax follows Papilio machaon in this respect, regularly eating 

 its exuviae throughout its larval life. Aitken and Davidson (Ann. 

 Bomb. Nat. Hut. Soc, v., p. 368) also note that the young larva of the 

 Indian species, Papilio liomedon, eats its cast skin. The mode of feed- 

 ing varies considerably among the various species, but, except when 

 very young, and sometimes even then, the larvae eat through the whole 

 thickness of the leaf ; the species vary too, as to the time at which 

 they feed, e.g., Mathew says that the larvae of Papilio erectlieus feed' 

 only by day, remaining perfectly quiescent throughout the night, but 

 Floersheim sa)S that the larva of Papilio machaon will feed at any 

 time from early morning until after sunset, but some will feed 

 long after others have ceased to do so ; the larva, when feeding, usually 

 rests with its head towards apex, and eats right down it from apex of 

 base, always resting, it appears, on the upperside of the leaf when so 

 engaged. On the other hand, the larva of Iphielides ajax, like Papilio 

 erectheus, feeds entirely during the day, and rests on the underside of 

 the leaf when so engaged, eating, at first, small circular holes out of 

 the leaves, but, later, from apex to base of leaf, retreating down the 

 midrib as it feeds. The young gregarious larvae of Laertias philenor 

 feed on the underside of the leaves of their foodplant, but, when older, 

 and especially when full-grown, feed on the stems in preference to 

 the leaves ; the real reason for the larger larva 1 not walking on the 

 upperside of the leaves, is that they are rarely sufficiently flattened to 

 afford a foothold, and that, being exceedingly active, and not accustomed 

 to spin much silk, they are liable to fall oil' the upperside of the 

 Aristolochia leaves. Floersheim notes (Ent. lire, x\i., p. 147) that two 

 or three larvae will simultaneously devour a stem of Aristolochia, com- 

 pletely enveloping it, so that no green is to be seen, and will feed it down, 

 with their heads almost touching from several sides at the same time. 

 The Sumatran species, Menelaides (Papilio) antiphus, also devours the 

 stalks, as well as the leaves of Aristolochia indica, whilst another Suma- 

 tra!] species, Troides amphyrsus, that feeds on a creeper with large trilo- 



