October g, 1919] 



NATURE 



123 



virtually the same unusual pattern in the Mynes as in 

 the Pierines seems to call for some explanation other 

 than an appeal to chance or accident. .Moreover, with 

 regard to the Pierines themselves, the two members of 

 the genus Delias are, of course, fairly closely related ; 

 but the Huphina belongs to an entirely distinct genus, 

 separated from Delias by many im[Xirtant structural 

 differences. The two six'cies of Delias perhaps depart 

 less widely in aspect from their nearest congeners than 

 does either the Huphina or the Mynes. The under 

 surface of the Jii-'phina is unexampled in its genus, 

 but the upper surface is quite ordinary. The Mynes, 

 as vve have seen, stands alone among its nearest rela- 

 tives not only in the chciracter of its under surface, but 

 also in the Pierine-like character of its wings above. 



We will now turn to another assemblage, which pre- 

 sents us with the same problem from a somewhat 

 different point of view. In south-eastern Asia, with 

 certain of the adjacent islands, is found a genus of 

 large butterflies, called by Wallace Prioneris from the 

 saw-like front inargin of the forewing in the male. 

 More than fiftv years ago it was remarked by Wallace 

 that the species of Prioneris in several cases seem to 

 mimic those of the genus Delias, and that "in all 

 cases the pairs which resemble each other inhabit the 

 same district, and very often are known to come from 

 the same locality." The parallelism is even stronger 

 I' than was stated by Wallace, for there is not a single 

 known member of the genus Prioneris which does not 

 resemble a species of Delias, so that Prioneris cannot 

 reallv be said to have an asf)ect of its own. Prioneris 

 clcmanlhe and Delias agostina form a pair inhabiting 

 the Himalavas, Burma, and Further India. In the 

 same region occur Prioneris thestylis and Delias bella- 

 donna, the striking similarity of which species, es])eci- 

 allv on the underside and in the female, drew the 

 special attention of Mr. Wallace. A still more remark- 

 able instance is that of Prioneris sita of southern India 

 and Ceylon, the likeness of which to the common 

 Indian Delias eucharis is sjxjken of by Wallace as 

 "ps'rfect "; while Fruhstorfer, a hostile witness, testi- 

 fies to the fact that the Prioneris always flies in com- 

 panv with the Delias, and rests just like the latter 

 with closed wings on the red flowers of the Lantana. 

 Prioneris hyt>sipvle of Sumatra and P. aiitnthisbc of 

 Java are like Delias egialea and D. criihoe of the same 

 two islands. Here again Fruhstorfer sa\s of Prioneris 

 aiitothisbe that it visits the flowers of the Cinchona, 

 "always in company with the similarly coloured Delias 

 critlioe." Wallace remarked on the close similarity 

 between Prioneris Cornelia of Borneo and Delias 

 singhul>iira of the Malay Peninsula; in this case, it 

 will be noted, the localities, though not far distant 

 from each other, are not identical. But a Delias form 

 which was unknown at the date of Wallace's paper has 

 since been found in Borneo, and this latter butterfly, 

 known as D. indistincta, is even more exactly copied 

 bv P. Cornelia than is the Delias which first drew Wal- 

 lace's attention. Prioneris vollcnhovii of Borneo is a 

 kind of compromise between Delias indistincta and, 

 on the underside, D. pandemia of the same island, and 

 it mav bp added that another Bornean Pierine, 

 Huphina pactolica, is a good copy of Delias indistincta, 

 therefore resembling also the Bornean Prioneris Cor- 

 nelia and P. vollenhovii. 



The memoir, published in 1867, in which Wallace 

 remarked on the parallelism between Prioneris and 

 Delias, contains a noteworthy prediction by the same 

 author. Speaking of Pieris (now called Huphina) laeta 

 of Timor, he says that it "departs so much from the 

 style of colouring of its allies and approaches so nearly 

 to that of Thyca (Delias) belisama of Java, that I 

 should almost look for an ally of the last species to be 

 discovered in Timor to serve as its pattern." Thirty- 



NO. 2606, VOL. 104] 



four years after the expression of this anticipation, Mr. 

 Doherty discovered in Tiinor an ally of Delias belisama 

 which at once suggests itself as the model from which 

 the i>eculiar and brilliant colouring of Huphina laeta 

 has been derived. Fruhstorfer, who is by no means 

 friendly to the theory of mimicry, says of this Delias, 

 which was named splendida by Lord Rothschild, that 

 beneath it is "deceptively like Huphina laeta." But 

 here comes in a curious jx)int. The black forewing 

 with its yellow ape.x and the orange-yellow hindwing 

 with its scarlet black-bordered costal streak are present 

 on the underside of both the Delias and the Huphina; 

 but the latter butterfly jxissesses, in addition to these 

 features, a row of scarlet marginal spots on the hind- 

 wing which are not to be found on the Delias. In 

 spite of this discrepancy, the likeness is sufficiently 

 striking. But from the same island of Timor, Doherty 

 sent home another Delias which, besides resembling 

 D. splendida, possesses a row of scarlet patches in the 

 corresponding situation to those of H. laeta. In this 

 latter Delias, however, named dohertyi by Lord Roth- 

 schild after its discoverer, the brilliant scarlet costal 

 streak is completely absent. The Huphina, therefore, 

 is more like either species of Delias than they are like 

 each other, forming, as it were, a link between them. 

 .So that, adopting Professor Poulton's terminology, we 

 may say that, if this is a case of mimicry, one form 

 ma}' possess at the same time the aposemes belonging 

 to two distinct models. I will not now stop to discuss 

 the bearing of this case on current theories, but will 

 only remark that, granting mimicry, the whole assem- 

 blage, D. splciuiida, II. laeta, D. dohertyi, may be 

 expected to gain advantage from the blending action 

 of the intermediate H. laeta. This I think would 

 happen whether laeta is a " Batesian " or " Miillerian " 

 mimic, but the gain to the association in the latter 

 case is certainly the more obvious. 



This state of things would be sufficiently curious if 

 it stood by it.self. But it does not stand by itself. In 

 Iximbok, Sumbawa, and Flores there occurs another 

 member of the peculiar group of Huphina to which 

 H. laeta belongs. This butterfly, known as H. 

 tettiena, resembles H. laeta in many respects; possess- 

 ing on the underside of the hindwing a scarlet costal 

 streak and a row of scarlet marginal spots like those 

 of that insect. The forewing, however, differs from 

 that of H. laeta in having its ground-colour not uni- 

 formly black, but divided between a dark shading to 

 the veins, a dark submarginal band, and series of pale 

 streaks and patches in the interspaces between the 

 veins. The question at once suggests itself : Is there 

 a relation between H. teniena and one or more species 

 of Delias corresponding to that between H. laeta and 

 D. splctidida and dohertyi? The answer to this ques- 

 tion is in the affirmative. Delias oraia, together with 

 Delias sumbawana, both species inhabiting the same 

 three islands as //. teniena, form with it an assemblage 

 quite comparable with the former triad from Timor. 

 Further, the points in which H. temena differs from 

 H. laeta have their counterpart in the distinctions be- 

 tween D. oraia and D. splendida on the one hand, and 

 D. sumbawana and D. dohertyi on the other. These 

 points are chiefly, in the temena assemblage, the less 

 dcfinitelv black-bordered costal streak, the more 

 stiongly-marked black bordering to the submarginal 

 scarlet spots, and the diverselvTColoured as compared 

 with the uniformlv black forewing of the Timor 

 insects. 



Again, in the island of Bali, Huphina tamar would 

 seem to combine certain features of two species of 

 Delias in a similar manner to the cases of laeta and 

 temena just considered. The underside as a whole, is 

 reminiscent of D. periboea, a member, like D. 

 dohertyi and D. sumbawana, of the eucharis or hypa- 



