PRESIDENTIAL ADDRESS. 201 



deal of the time spent, say, on Greek and Latin prose and verse writing, might 

 in my case have been Vvfell spared for other objects. 



To generalise what I have been saying. Start teaching your boy or girl on 

 a good wide basis. Nothing is better for this than the old school subjects of 

 classics, history and mathematics, with the addition of natural science. In 

 course of time a bent will declare itself. Encourage this, even at the expense of 

 other studies desirable in themselves. But do not allow any one subject, however 

 congenial, to usurp the place of a grounding in those matters which are proper 

 to a general education. The time for specialising will come ; and when it has 

 arrived do all you can to remove obstacles, pecuniary and other. Do not hamper 

 your historian with chemistry or your zoologist with the differential calculus. If 

 they have a taste for these things by way of diversion or recreation, well and 

 good. But let their action be voluntary. 



This, however, is not a fitting occasion for propounding my views on the 

 question of education, and it is time to turn to the immediate object of my 

 address. And here I think I cannot do better than to bring before your notice 

 certain facts which have a bearing on the subject of insect mimicry; a subject 

 which for many years past has engaged much of my attention. The facts on 

 all hands are allowed to be remarkable. As to their interpretation there is much 

 diversity of opinion; and indeed, until complete data are forthcoming, this 

 could hardly be otherwise. 



The Geographical Factor in Mimicry. 



In the first place let us glance at a certain assemblage of butterflies that 

 inhabits New Guinea with some of the adjacent islands. These butterflies, 

 though belonging to different subfamilies, present a resemblance to each other 

 which is too strong to be accidental. Three of them belong to the Pierines, the 

 group which includes the common white butterflies of this country ; the fourth is 

 a Nymphaline, not widely removed from our well-known tortoiseshells, red 

 admiral and peacock. The resemblance on the upper surface tetween two of the 

 three Pierines is not especially noteworthy, inasmuch as they present in common 

 the ordinary Pierine appearance of a white or nearly white ground colour with 

 a dark border somewhat broadened at the apex. But this, an everyday feature 

 in the Pierines, is almost unknown in the very large subfamily to which our 

 present Nymphaline belongs. (Still, though sufficiently remarkable to arrest 

 the attention of anyone familiar with these groups, the Pierine-like aspect of the 

 upper siirface of this Nymphaline, which is known as Mynes doryca, would 

 not by itself have seemed to call for any special explanation. The resemblance 

 would pass as merely an interesting coincidence. But the under surface of the 

 three Pierines, known respectively as Hujjhinn ahnormis, Delias ornytion and 

 Delias irma, presents a striking combination of colour very unusual in their own 

 group ; and this peculiar character of the under surface is shared by the 

 Nymphaline Mynes doryca. The ' long arm of coincidence ' could scarcely reach 

 as far as this. Whatever might be said about the likeness seen from above, 

 that the wings beneath should show 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 Hvphina belongs to an entirely distinct genus, separated from Delias by 

 many important structural differences. The two species of Delias perhaps 

 depart less widely in aspect from their nearest congeners than does either the 

 Hupfiino or the Mynes. The under surface of the Hvphina is unexampled in 

 its genus, but the upper surface is quite ordinary. The Mynes, as we have 

 seen, stands alone among its nearest relatives not only in the character of its 

 under surface, but also in the Pierine-like character of its wings above. 



We will now turn to another assemblage, which presents 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 Priove.ris from the saw-like front margin of the forewing in the male. 

 More than fifty years ago it was remarked by Wallace that the species of Prioneris 



