HABITS OF LARV^ OF LAERTIAS PHILENOR. 147 



side of a leaf it may be found resting at the end of a stem of a very 

 young shoot of Arisfnlochia. A noticeable feature of the adult larva is 

 its helplessness after exuviation, it remains flaccid for some hours, and 

 does not begin to feed again almost at once as P. machaon does. 



(4) When full-grown the larva of /.. philenor, though still exceed- 

 ingly sociable, is not strictly gregarious. Scudder (quoted A Natural 

 History British Butterfiies, i., p. 67) is wrong when he talks of the larvae 

 of the species concealing themselves for protective purposes " beneath 

 the broad leaves of Ariatolorhia.'" L. philenor only keeps to the under- 

 side of the leaves when young or when about to undergo ecdysis ; and 

 the probable explanation of the fact that it does not feed usually, even 

 when full-grown, upon the upperside of the leaves, is that, being 

 exceedingly active, and except at times of exuviation, not accustomed 

 to spin much silk, it is liable to fall oft' the uppersides of the Aristo- 

 lochia leaves {cf. Scudder, ButterftieH of Keiv England, vol. ii., p. 

 1249). (I have not noticed it spinning zigzag lines of silk on surfaces 

 of leaves, though I have often seen it fall off, even when undisturbed). 

 Otherwise it is difficult to account for the habit of the full-grown larva 

 of L. /i/tilenor to feed on the stems of the young growth of Aristolochia 

 siplto rather than the leaves even when there is an abundance of the 

 latter at hand, whilst fully exposed in companies of two and three, and 

 its fondness for sunning itself, whilst not feeding, on the topmost stems 

 of its food-plants or on their bare wooden supports, where it is a most 

 conspicuous object. In addition to this I have often seen this larva 

 when full-grown feeding on the upperside of the topmost leaves, often 

 sufficiently flattened to afford it a foothold, with nothing between it 

 and the sky above. A noticeable habit of the full-grown larva is that 

 two or three will simultaneously devour a stem of AriMolochia, com- 

 pletely enveloping it, so that no green is to be seen, and feeding it 

 down with their heads almost touching from several sides at the same 

 time. 



(5) Food-habit. — It seems to be confined to Aristolochia, the 5 s rarely 

 ovipositing on plants of neighbouring families (Scudder, op. cit., vol. 

 ii., 124). Mine were all fed up upon Aristolochia sipho : but when this 

 ran short they would eat, though not with the same avidity, the 

 leaves and stems of A. elcmatidis. 



(6) The larvae, at all stages, sleep where they rest or stop feeding, 

 and their sleeping-position is the same as their resting one. 



(7) With regard to Laertios philenor throwing forwards or laggards 

 in the larval state, I have been unable to segregate the many batches 

 of larva? sufficiently to have data for passing an opinion, but it is 

 quite certain that some of the resulting pupae have a tendency to 

 produce imagines earlier than the bulk. It has been my habit each 

 year to collect the pupae of L. pldlenor as soon as they are hardened 

 enough to detach, and to place them in a cool, thatched apple- house. 

 Of these about ten per cent, will produce a partial second -brood as 

 with 1'. machaon in the same circumstances, the number varying some- 

 what with the intensity of the early autumn sunshine, but the imagines 

 do not always result from the pupae first formed, though the last 

 formed ones have a distinct tendency to go over the winter as such. 

 Of this I am sure, as I place the pupae collected at different times on 

 different shelves. 



(8) Laertias pldlenor in its larval state is exceedingly active after 

 its middle stadium, and will often crawl a distance of two or three 



