816 THE entomologist's recokd. 



rot. The ovum when laid is of a straw colour, and under a fairly powerful 

 magnifying glass (I, alas ! had no microscope by me) is almost indis- 

 tinguishable from that of P. iitachaon. In a few days it darkens in 

 tint to a pale brown, and has often a well-marked horizontal band of 

 dark brown about half-way between its middle and its base. Before 

 hatching it turns to a leaden-black. Though the larva in its last 

 stadium is often considerably larger, both in respect of length and of 

 stoutness than that of any of 1'. mac/uKni I have ever seen, I was unable 

 to detect any corresponding ditference in the size of the ovum. The 

 young larvae when hatched, and, indeed, until its last two instars, 

 resembles so closely that of P. iiiachaon, that I was unable to distinguish 

 between the two species. In its last instars, however, the five orange 

 spots on each of the black segmental bands in P. machaon are replaced 

 in P. asterias by correspondmg spots of a rich chrome-yellow, but of 

 twice the size and of a rounder shape. The larva of P. aHterian, in 

 addition to differing from P. machaon in this respect, has a slightly 

 bluer and less vivid green for its ground colour, and the black bands 

 are broader and always continuous. Besides being bulkier than that 

 of P. viachaon it is much more sluggish, and rarely crawls the distance 

 to pupate that the larva of P. tiiac/iau)i will. In its later stadia it is 

 only with difficulty that it can be induced to protrude its orange- 

 coloured osmaterium. I noticed also that some of my second -brood 

 larvae had much more black about them than those of the first. 



The pupa of P. asterias bears a strong family likeness to that of P. 

 machaun, but is generally larger and slenderer, tapering considerably 

 more in the anal segments. All its silken attachments, particularly 

 those of the wing-cases, are much more fragile than those of P. macliaon, 

 and it seems more fond of adopting a horizontal position than its 

 English relation. In colour, though dimorphic, its difference from the 

 latter is usually well marked enough, the white ground colour of the 

 brown variety being replaced by a generally greyer tint, whilst the brown 

 markings are lighter in hue. In the green and yellow variety, how- 

 ever, the opposite is the case, and the colours of P. asterias are more 

 vivid than those of any P. machaon I have ever noticed. Nevertheless, 

 in one or two cases the pupa so closely resembled a pale specimen of 

 the brown variety of P. macliaon, that I could only tell them apart 

 with difficulty. Perhaps this is a reversion to a less specialised form 

 of pupa. But perhaps this was due to the effect of cold upon the 

 pigmentary cells of the larva, as I have noticed the same phenomenon 

 in the larvae of Platysanria cecropia during an English autumn. In 

 case any captures of I'apiUo asterias, in Surrey, Berkshire, or Hants 

 are recorded, I may state that I set at liberty some sixty or seventy 

 specimens during the months of August and September. 



The relationship between P. asterias and P. machaon seems in any 

 case to be_a very close one, but next year, when I hope to compare the 

 ova and larvje of the two species under a microscope, I shall be able to 

 speak with more certainty regarding this. P. asterias seems to be in 

 some respects the more highly specialised of the two, notably in its 

 sexual dimorphism as an imago, and in its aversion from protruding its 

 osmateriumduringitslast stadium. It is acurious fact that, whilst Skim- 

 mia japonica is the favourite foodplant of /'. mac/iaoti, the larva of P. aste- 

 rias, though taking readily to all the rvibelUferae on M'hich P. viachaon 

 feeds, cannot be induced to touch Shimmia. The female parent of my 



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