NOTES ON PAPILIO MACHAON. 



15 



pointing towards tip of leaf, eating right across it, from apex to base. 

 P. nmchaon, both when young and old, will feed from early morning 

 until after sunset, but time for leaving off varies, some continuing to 

 feed long after otlaers have ceased to do so. All its life it consumes 

 its exuvias. 



V. Food-hahit — on Butaceae and Uinhelliferae. — Skiwntia oblata 

 {japonica) appears to be its favourite food-plant, the imagines in my 

 butterfly-house laying more eggs on this than even the fennel that 

 grows by its side, and the larvae feed up quicker on this than on any 

 other pabulum (the young succulent growths being preferred to the 

 leaves of the year before). Next to this I should place fennel. It will 

 also feed on rue and dittany {Dictainnus fra.vinella), preferring the 

 aromatic seed-pods of the latter, and on Ptelea, but the specimens 

 found on the last-named take at least twice as long to feed up as those 

 on Skimviia. I have never found ova or larvae on beaked-parsley or 

 cow-parsnip, though both of these grow in my butterfly-house. 



VI. Sleepimi-habit. — When young, on upperside of leaf, with head 

 generally pointing towards stem and slightly raised, and with thoracic 

 legs clasped — often down the midrib of leaf — in fact, the sleeping- 

 habit is the same as the complete resting-habit, and the larva does 

 not appear to move from its resting-place. On fennel, also, with head 

 pointing inward from tip of leaf towards the main stem. When older, 

 indistinguishable from resting-habit. 



VII. Forward, or lat/nard habit. — Every summer some one or two 

 per cent, of my P. machaon larvt^ produce a partial second-brood, and 

 in a warm one like the present (1908), as many as five x^er cent. did so ; 

 the imagines appearing from July 30th till August 15th. The pup« of 

 these were amongst the early-formed ones, but not, in all cases amongst 

 the very earliest. Indeed, out of the twelve first pupae I found, only 

 two produced second-brood imagines, in spite of my subjecting them to 

 a forcing heat in a vinery for more than three weeks. The others lived, 

 but obstinately refused to be forced, whilst others which had pupated 

 a week later gave rise to imagines under natural conditions. From 

 what I have observed, I should say that, though all P. machaon larvae 

 which result in a second-brood feed up rapidly, many of those which 

 feed up rapidly do not disclose a second-brood. With regard to the 

 " forward " and " laggard" habit amongst the larvae themselves, there is a 

 great variety in the time taken to feed up, the last larv;e, though 

 resulting from ova laid during the first part of July, not pupating 

 until the end of the first fortnight in September, whilst the bulk, 

 though they take a longer time to feed up than the very first, certainly 

 did not take more than two-thirds of the time spent by the laggards. 

 I should say that the partial second -brood of P. machaon spends from 

 about three weeks to a month in the pupal state. 



VIII. Movements. — The larva of P. machaon is exceedingly sluggish 

 in its habits, particularly when young, and I have known it starve on 

 a withered leaf rather than migrate to a living one touching this. I 

 have never observed it move backwards when young, and, when older, 

 only gradually, as it finds the leaf it is eating across disappearing in 

 front of it. It will, however, when young, shake its head sharply 

 from side to side {cf. antea), and, when older, if an aphis settles on it, 

 probably in the latter case mistaking an aphis for an ichneumon. It 

 never retreats to a sheltered position in wet weather. 



