Variation and aberration in butterflies. 75 



and warmer season of the year, that many well-marked differences 

 — as is partly known, partly still unrecognised — present them- 

 selves in the shape of the wings. For this purpose the other 

 portions of the body need scarcely be taken into account. These 

 differences, however, show opposite relations in different species; 

 for whereas Papilio podalirius, L., P. machaon, L., P. hospiton, 

 Gene (when it exceptionally produces a second brood), Poly- 

 omniatus tkersamon, Esp., P. plilccas, L., Lyccena argiades, Pallas, 

 and others (see ' Insekten-Borse,' Leipzig, April 15th, 189-1) 

 have their summer form provided with longer tails, and in many 

 cases with a more acute fore wing, as well as a more deeply 

 waved border to the hind wing, Vanessa c-album, L., and V. egea, 

 Cr., show just the opposite ; for in these species the summer 

 form presents the less, and the winter form the greater, amount 

 of indentation. 



(3) Moreover, with reference to the colours and markings of 

 the wings and of the upper surface of thorax and abdomen (for 

 these latter must also be taken into account) it is not possible to 

 establish any invariable relation between the imago and the larva 

 reared at a raised temperature. Lasiocampa var. (sstiva, Stgr., 

 and var. autumnalis, Jaenich, as also Urapteryx var. olivacea, 

 Stdfs., become darker than the ordinary forms L. populifolia, 

 Esp., and U. sambucaria, L., derived from hybernated larvae, by 

 an mcrease in the dark elements of the pattern. On the other 

 hand, Dasychira abietis, Schiff., Bind D. piidibunda,Ij., have their 

 second brood lighter in consequence of a reduction in the number 

 of dark scales. To adduce a few similar instances from those 

 that occur in nature : Papilio podalirius, L., P. machaon, L., 

 Pieris krueperi, ^tgr., napi, L., daplidice, L., Anthocharis belemia, 

 Esp., belia, Cr., Leucophasia sinapis, L., Lytkria purpuraria, L., 

 take on, under an increase of warmth, lighter and for the most 

 part cruder and brighter colours. On the other hand, Poly- 

 ommatus phloeas, L., P. amphidamas, Esp., Vanessa levana, L., 

 become more dusky under the same conditions (see Zeller, ' Isis 

 von Oken,' 1847, p. 213; Weismann, 'Ueber den Saison-Dimor- 

 phismus der Scnmetterlinge,' Leipzig, 1875 ; Seitz, Stettin 

 Entom. Zeitschrilt, 1894, pp. 290—307 ; Standi'uss, ' Handbuch 

 lur Sammler der europaischen Gross-schmetterlinge,' Guben, 

 1891, pp. 119—125). 



Secondly — as to food— I have also recorded, in my 'Manual,' 

 pp. 116 — 119, all the facts known to me, whether from the 

 carefal researches of other trustworthy entomologists, or from 

 my own observations. Here I need only devote a few words to 

 the subject, especially as the experiments, taken together, only 

 yielded results which were actually or virtually negative. 



The feeding of polyphagous larvse on leaves of monkshood 

 (Acomtmn sp.), walnut {Juglans sp.), deadly nightshade {Atropa 

 belladonna, L.), the root of the carrot {Dauciis carota, L.), raw 



