NOTES ON THE EARLIER STAGES OF PAPILIO MACHAON. 279 



the pnpa to rot. Amongst the HOO ov so pnpje which J collected this 

 year, in four instances only did I find one upon a tree or a perishable 

 stem such as grass. Two of these were green pupae upon terminal 

 shoots of willow resting upon a Skiunnia bush, one a green pupa 

 attached to a grass stem but resting against the side of the butterfly- 

 house itself, whilst the fourth was a brown pupa amongst Slniiniiid 

 twigs, but on the trunk of a young plum-tree growing out of a Skiiiuiiia 

 bush. In all other cases the pupa^ were found upon Skiiniiiia, lavender, 

 a non-deciduous Lmiicera, London Pride, etc., where they would be 

 exposed neither to the birds nor to the wet and mud. For the past 

 four years I had observed the same phenomenon, and, to test the 

 instinct of my larvae, grew a number of sweet-peas, zinnias, annual 

 valerian, etc., near the foodplants. I found that, though in some 

 instiinces the pupa? were attached to the solid sticks running through 

 and supporting the sweet-peas, valerian, etc., in no case had the insect's 

 instinct betrayed it. This year I found the larvae of Papilio nsterias 

 pupatnig, though in one or two cases only, on fennel, but as this species 

 has a succession of broods in its natural habitat, it would not run that 

 same risk. It would be interesting to know whether the summer brood 

 of P. niachanv, in south Europe, ever pupates on such perishable stems. 

 With regard to the disputed double-broodedness of P. viacliaon in 

 England, I may mention that one of my 800 pup«, though kept out- 

 of-doors and in all respects under the same conditions as the others, 

 produced an imago on August 20th. This, a female, was a large 

 specimen, and paler than the wont of English ones. 



In addition to the pupae which I have already enumerated in this 

 article, there were some thirty others which Avere stung by the minute 

 black Ichneumon Avhich particularly aft'ects /'. inarlunm. I may add 

 that in no instance have I yet observed the parasite in question attack 

 the larva, but itlways the newly-formed pupa, which it .searches for 

 among the Skiuimia leaves, etc. The attack appears to be always 

 made immediately, or in a few hours, after pupation, before the 

 chitinous envelope of the pupa has hardened. I have frequently 

 watched the ichneumon tiies wandering over the hardened pupa which 

 I have collected from the bushes and suspended, evidently seeking in 

 vain for some soft spot in the puparium in which to lay their eggs as 

 they play over its surface with their antennre. The pupa of P. iiiarhao)i 

 I have also found subject to the attack of predaceous beetles : but of 

 these and their relentless enmity to the lepidoptera, I hope to deal in 

 a succeeding article. In conclusion, 1 would like to point out a fact 

 which I think may be of some interest to those who study the evolution 

 of the life-habits of lepidoptera. Having come across several larvae 

 of /-*. Diachaon in the act of pupation, it struck me that it would be 

 interesting to see whether the lateral wriggling of the newly-disclosed 

 pupa, in its efforts to get rid of the larval skin immediately after the 

 attachment of the cremaster, would cease upon the removal of the skin 

 in question. I found, however, that the pupa still continued its efforts 

 for some time, a fact which seems to prove that the struggles to get 

 rid of the larval skin do not respond to any stimulus caused by the 

 individual skin, but are merely generic. Next year I will compare the 

 duration of those movements in pupa' which have had the skin 

 removed artificinlly and in those with which the process is a natural 

 one. 



