PRESIDENTIAL ADDRESS. 203 



docs not stand by itself. In tombok, Sumbawa and Flores there occurs another 

 member of the peculiar group of Hupliina to which H. lacta belongs. This 

 butterfly, known as H. tcmena. resembles H. laeta in many respects; possessing 

 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 uniformly 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. temena and one or more 

 species of Delias corresponding to that between H. laeta and D. splendida and 

 dohertyil The answer to this question is in the aflSrmative. Delias oraia, 

 together with Delias sumhawana, both species inhabiting the same three islands 

 as H. temena, 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 between D. oraia and D. splendida 

 on the one hand, and D. sumhawana and D. dohertyi on the other. These points 

 are chiefly, in the temena assemblage, the less definitely black-bordered costal 

 streak, the more strongly-marked black bordering to the submarginal scarlet 

 spots, and the diversely-coloured as compared with the uniformly 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. sumhawana, of the eucharis or hyparete group 

 of the genus ; while the red costal streak suggests the influence of a representative 

 in Bali of the lelisama group, like D. splendida and D. oraia in the other islands. 



Finally, in the island of Sumba we have another member of this remarkable 

 group of Huphinas. Huphina julia, the butterfly referred to, so closely 

 resembles Delias fasciata of the same island, that even the sceptical Fruhstorfer 

 is constrained to speak of it as a ' faithful copy ' of that insect. But here once 

 more it is noticeable that one of the most conspicuous features of the Huphina 

 is absent from the Delias. This time it is not, as in the case of D. splendida, 

 the submarginal row of scarlet spots on the underside of the hindwing, but it 

 is the scarlet costal streak that is wanting. Huphina julia was discovered by 

 Mr. Doherty in the year 1887, and described in 1891. It is interesting, in the 

 light of what is now known of the butterfly fauna of the Lesser Sunda islands, 

 to read what Doherty has to say about the mimicry question in relation to the 

 Delias and Huphina forms that have just been mentioned. Speaking of H. julia, 

 he says, ' If it stood alone, I should certainly suppose it to be a mimic of some 

 form of Delias hyparete yet undiscovered in the island. Biit both H. laeta and 

 H. temena require to be accounted for in the same way, and while it is possible 

 that some Timorese Delias may resemble H. laeta, I feel sure that H. temena 

 can have no such original. It must then be assumed that this group is less 

 pressed by its enemies in the Timorian Islands, and has therefore been able 

 to acquire more brilliant colours than its allies.' So far Doherty. 



Whatever may be the value of this last hypothesis, we have just seen that 

 the supposed facts on which it rests are non-existent, for (1) the 'form of 

 Delias Hyparete as yet undiscovered ' has actually turned up in the person of 

 D. fasciata; (2) it is not only possible, but actually the case that ' some Timorese 

 Delias may resemble H. laeta ' ; (3) Mr. Doherty ' feels sure that H. temena 

 nan have no such original,' but Delias oraia and Delias sumhawana have just 

 the same rc'lation to Hvphina temena as I). spJendida and D. dohertyi to H. laeta. 

 In view of these facts it may be not rash to suppose that the apparent absence 

 of a model for the red costal streak of H. julia may hereafter be accounted for. 



Of the three instances of possible mimetic nssnciation -which have now been 

 mentioned, I think that only one — viz., the first, has previously been treated in 

 deta'l. The numbers of cases more or less similar tn these three might be very 

 largely extended, but for our present purpose it will be sufficient to confine our 

 attention to those already given. It is probable that to some minds the facts 

 adduced are simply curious coincidences, needing no explanation : but it can 

 hardly be wron^r to suppose that to most students of Nature the observe<l 

 phenomena do mil for some attempt at interpretation ; and on a review of the 



