HARDWICKE'S SCIENCE-GOSSIP. 



109 



be made, its generation will prove recent indeed 

 among butterfly races. 



Had the box been sent from any other place verging 

 on the boundary zone of the European Asiatic, or, in 

 technical language, the Palcearctic region ; from one 

 of my well-wishers, say, resident in Siberia, North 

 America, China, Persia, Syria, Algeria, or the 

 Canaries, the result would have been the same ; even 

 the remote island of the Mikado, as Mr. A. G. Butler 

 most kindly brought to my notice the other day, con- 

 taining strange giant races of our well-known night- 

 fliers of the lantern and sugar-pot. In this case the 

 water expanses of the Kamtchatkan and Mediter- 

 ranean seas do not materially affect the distribution ; 

 but had the box been from parts more remote, the 

 species would have been less allied in character to 

 those that fly around us in the woods and meadows, 

 the most distinct and specialised region with little 

 doubt proving to be the forests of the Brazils. 



Since we conclude from entomological observation, 

 as from the record of the rocks, that an incessant 

 extirpation and variation of species has combined 

 with the agency of man in rendering the surface of 

 Europe what we see it, it becomes not a little curious 

 should we find in the butterfly fauna a tendency, under 

 certain conditions of climate or otherwise, to fluctuate 

 in the direction of these bordering forms. Let us take, 

 for example, our small tortoiseshell. This butterfly, 

 as I have already noticed, towards the north and east 

 of the European area as on elevations in this country, 

 scarfs itself in black and dispenses with its two wing- 

 flecks. It likewise from time to time evolves another 

 variety, an example of which I have just netted on 

 the Surrey hills, that shows a yellow line running 

 exteriorly to the black band. But only once unite 

 these characters in an individual, and there is no 

 evidence that such permutation is not in harmony 

 with experience ; and you will have presented to the 

 mind a butterfly that a mere touch of the tar-brush 

 would render undistinguishable from the somewhat 

 scarce tortoiseshell of Canada, Vanessa Milberti, God. 

 In order that comparison may be made by any 

 variety breeder, who, having obtained his black- 

 banded tortoiseshells, has yet greater aspirations, I 

 give a figure of this insect from a specimen kindly 

 sent me for the purpose by Dr. Haydon from the far 

 off Hudson's Bay (fig. 76). As another example in 

 passing, I might mention the American gooseberry 

 moth, buff with black bands, and the caterpillars of 

 our own gooseberry destroyer {Abraxas grossidariata) 

 which, similarly pied, produces buff and black-banded 

 moths occasionally. 



Besides fluctuating in the direction of outlying 

 races, butterfly forms approach and recede on the 

 European area ; a familiar instance occurring to me 

 in a large tortoiseshell only lately bred from a brood 

 of the smaller kind by Mr. William White, of the 

 Epping Forest Field Club. Was it a large tortoise- 

 shell or not ? doubtless many have already inquired, 



and were they also large tortoiseshells obtained pre- 

 viously by Mr. Tawell from a brood of the same 

 butterfly ? Well, in the first instance I believe the 

 matter is not unprecedented ; and if we accept 

 Frofessor Huxley's definition, and consider every 

 butterfly form as virtually having a constant part of 

 its organisation A in common with others, and a 

 variable difference n, then there can exist no doubt, 

 as I picture to myself, but that the butterfly has 

 really relapsed into the type of the larger strong- 

 winged sort, and reverted probably to an older form. 

 For I think the matter will bear of being fairly 

 resolved in this way. As Mr. White justly remarks, 

 our large brown tortoiseshell is very much more 

 constant in its wing-design than the smaller species 

 is. The female is also pre-eminently single-brooded, 

 laying her eggs during the sunny hours of spring, 

 when alone elm-leaves are sappy and palatable to 

 caterpillars ; whereas her lowly congeners, floating 

 about the succulent nettle patches, can there reproduce 

 in many a ruddy generation throughout the warm 

 summer months. As far as I can determine from 

 my album of water-colour sketches, that variety of 

 small tortoiseshell caterpillar that has the yellow lace, 

 approaches closely in appearance the usual form of 

 caterpillar belonging to the larger butterfly ; and as 

 all such finery tarnishes and turns black here in the 

 hedges about the first of August, I consider these 

 yellow-banded caterpillars as typically a summer 

 form ; and Urticae and Polychloros, united in most 

 cabinets by intermediate sports, to be the extremes of 

 variation. 



Some will doubtless conclude from this, that when 

 glacial summers were, the short season only permitted 

 of the existence of a one-brooded butterfly ; and that 

 as brighter years dawned, more broods were pro- 

 duced and variation ensued by seasonal varieties 

 becoming permanent. Others again may think, the 

 variation came about when the species first took to 

 feed on the more succulent plant ; and that this is, 

 of course, merely a matter of adaptation, any may 

 prove for themselves by mixing fresh elm-shoots with 

 the nettle-leaves, and in this way inducing the 

 caterpillars of the small tortoiseshell to relinquish 

 their proper food for that of their congener. But as 

 extremes will by no means negative means, and as 

 some other existing butterflies as regards colour, shade, 

 and pattern seem to lie between Urticae and Poly- 

 chloros, it would seem here a common ancestry is 

 indicated, butterfly distinctions being invariably 

 fine spun even, to the initiated. Indeed I conceive if 

 any one will make a study of a perfect series of the 

 group as now known, he will come to observe how it 

 parts into a subdivision of butterflies, that like our 

 native Comma, have a scollop in the fore wing. If 

 he then single out two very similar butterflies with 

 this ragged appearance, /. album and V. album, 

 inhabiting Europe and Northern America respec- 

 tively, he will come to observe how we may on the 



