January 27, 1898] 



NATURE 



305 



Malayan Islands, had observed and was able to adduce a strictly 

 analogous series of mimetic resemblances among Oriental butter- 

 flies, and gave his unreserved acceptance of the Batesian mter- 

 pretation. Such support from the co-founder with Darwm of the 

 theory of natural selection, and from a naturalist of the widest 

 experience in both Western and Eastern tropics, was of the 

 greatest weight with evolutionists generally. 



My own contribution to the subject was read to the Lmnean 

 Society in March 1868. In the previous year I had made an 

 entomological tour in Natal, and had enjoyed some precious 

 opportunities of observing in nature several cases of mimicry 

 between species not inhabiting the Cape Colony. There was no 

 claim to originality in my paper ; it simply rounded off the case 

 by adding from Africa, the third great tropical region of the 

 globe, a series of instances and observed facts confirmatory of 

 those brought forward by Bates from the Neotropical, and by 

 Wallace from the Oriental region. Of course I had had nothing 

 like the extended field experiences of those great naturalists, and 

 the African material then available was but scanty ; but it so 

 happened that perhaps the most striking and elaborate of all 

 recorded cases of mimicry— that exhibited by the females of the 

 Merope-^xo\x^ of Papilio — had come under my personal observa- 

 tion in South Africa, and I was thus in a position to describe 

 satisfactorily a wonderful illustration of the Batesian theory. ^ 



It will be remembered that Bates, in his memorable paper, 

 also brought to notice the very close resemblances, or apparent 

 mimicries, which unquestionably exist between species belonging 

 to different groups or subfamilies of protected distasteful butter- 

 flies themselves ; but neither he nor Wallace felt able to give 

 any explanation of these instances, which obviously differed very 

 materially from the cases of mimicry of an unpalatable protected 

 species by a palatable unprotected one. Not until 1879 was there 

 any elucidation of this side of the matter, but in May of that year 

 appeared in Kosmos, Fritz Miiller's notable paper on " Ihtna and 

 TAyrt'dta," which was translated by Prof. Meldola, and printed 

 in our Proceedings for the same year (p. xx. ). In this memoir, 

 Miiller made the valuable suggestion that the advantage derivable 

 from these resemblances between protected forms was the division 

 between two species of the percentage of victims to the in- 

 experience of young insectivorous enemies which every separate 

 species, however well protected by distastefulness, must pay. 



Prof. Meldola not only brought forward and supported, with 

 all his wonted grasp and acumen, F. Miiller's daring interpreta- 

 tion of this phenomenon, but in 1882, in a paper discussing the 

 objections brought against Muller's view, made a distinct advance 

 by showing how that view could justly be extended to explain 

 the characteristic and peculiar prevalence of one type of colour- 

 ing and marking throughout large numbers of species in pro- 

 tected groups — so especially noticeable in the sub-families 

 Danainse, Heliconiinse, and Acrseinse. 



In 1887 was published Prof. Poulton's most interesting 

 memoir entitled " The Experimental Proof of the Protective 

 Value of Colours and Markings in Insects in reference to their 

 Vertebrate Enemies," which dealt in great detail with the actual 

 results of numerous experiments conducted by himself and other 

 naturalists with the object of ascertaining to what extent highly 

 conspicuous (almost always distasteful) larvae and perfect insects 

 • are rejected or eaten by birds, lizards and frogs. The conclu- 

 sions given at the close of this paper cover a wide range in con- 

 nection with the subject of warning coloration, and among them 

 I would call special attention to No. 5, in which the author 

 points out that " In the various species in which a conspicuous 

 appearance is produced by colour and marking, the same colours 

 and patterns appear again and again repeated," and adds that 

 " In this way the vertebrate enemies are only compelled to learn 

 a few types of appearance, and the types themselves are of a kind 

 which such enemies most easily learn." This generalisation 

 certainly had the merit of first detecting a great additional ad- 

 vantage derivable from the common aspect exhibited by a 

 number of protected forms in the extended " Miillerian" asso- 

 ciations indicated by Prof. Meldola ; and it was applied by 

 Wallace to the case of the Heliconiidas in the comprehensive 

 survey of warning coloration and mimicry generally given in 

 " Darwinism." We are further indebted to Prof. Poulton for 



1 At various subsequent dates I was enabled, through the valuable aid of 

 Mr. J. P. Mansel Weale and Colonel J. H. Bowker, to make known to 

 science conclusive evidence of the species-identity of the three mimetic 

 females of Papilio cenea, and of the pairing of the widely -differing sexes of 

 that species. 



NO. T474. VOL 57] 



the discussion and summary of all extant data up to 1890 in his 

 "Colours of Animals" — a work which abounds in pregnant 

 suggestion, and indicates with justice and clearness how far the 

 evidence forthcoming was valid, and in what directions evidence 

 still lacking should be sought. 



Wallace well observed that ' ' to set forth adequately the 

 varied and surprising facts of mimicry would need a large and 

 copiously illustrated volume ; and no more interesting subject 

 could be taken up by a naturalist who has access to our great 

 collections and can devote the necessary time to search out the 

 many examples of mimicry that lie hidden in our museums." 

 A work ostensibly of this character was issued in 1892-93, in 

 two parts, from the pen of the late Dr. Erich Haase, under the 

 title of " Untersuchungen iiber die Mimicry auf Grundlage eines 

 natiirlichen Systems der Papilioniden " ; and last year an English 

 translation of the second part was published, and has quite 

 recently been reviewed by Prof. Poulton (Nature, November 

 4 and II, 1897). 



Recent Contributions to the Subject. 



Among recent contributions to the subject, we shall, I think, 

 all agree in assigning a high place to the memoirs with which 

 Dr. F. A. Dixey has enriched our Transactions. In 1894 he 

 read before the Society his elaborate paper " On the Phylogeny 

 of the Pierinse, as illustrated by their Wing-markings and 

 Geographical Distribution," and took occasion to discuss the 

 wide divergence from the primitive or typical pattern of the 

 group caused by mimicry in such genera as Euterpe, Pereute, 

 Dismorphia, Sec. Adopting the Miillerian interpretation as 

 expanded by Meldola, he proceeded to offer the original sug- 

 gestion that, in the acquisition of closer resemblance between 

 two or more protected forms, it was not necessary that in every 

 instance the process of adaptation should lie solely in the 

 imitation of one particular form as model, but that there might 

 very well exist mutual convergence of the forms concerned, 

 thus accelerating the attainment of the common beneficial 

 resemblance. This "reciprocal mimicry" the author further 

 explained in a paper read in 1896 " On the Relation of Mimetic 

 Patterns to the Original Form " (pp. 72-75), by a consideration 

 of certain mimetic sets of Heliconii, Pierinse, and Papilioninge 

 which present features and relations of pattern and colouring 

 explicable apparently in no other way than by the hypothesis 

 in question. This paper also gave a lucid demonstration, traced 

 through corresponding series of existing forms of both mimetic 

 and non-mimetic Pierinai, of " the successive steps through 

 which a complicated and practically perfect mimetic pattern 

 could be evolved in simple and easy stages from a form present- 

 ing merely the ordinary aspect of its own genus," and further 

 adduced reasons for holding that " it is not necessary that the 

 forms between which mimicry originates should possess consider- 

 able initial resemblance." In his latest memoir, "Mimetic 

 Attraction," read on May 5 last. Dr. Dixey expanded a sug- 

 gestion he had previously (1896) made respecting divergent 

 members of an inedible group to point out — still from evidence 

 in the Pierine subfamily to which he has devoted so much 

 fruitful study — " how the process of gradual assimilation starting 

 from one given point may take not one direction only but 

 several divergent paths at the same time," with the result that 

 a more or less intimate mimetic relation was brought about with 

 several protected forms of quite different affinities, though each 

 connected in their colouring and aspect with some group of 

 distasteful associates. He further set forth very fully the dis- 

 tinction which exists between the mimicry of inedible by edible 

 forms, which could only be in one direction and was of advantage 

 to the mimicker alone, and the assimilation among inedible forms 

 themselves, where the mimetic attraction acts reciprocally, to 

 the advantage of all participators. 



Another of our Fellows, Colonel C. Swinhoe, distinguished 

 for his wide and intimate knowledge of Oriental Lepidoptera, 

 read before the Linnean Society, in 1895, a most interesting 

 paper " On Mimicry in Butterflies of the genus Hypolimnas." 

 In this memoir, as the author points out, a small group of wide- 

 ranging mimetic insects is followed throughout its geographical 

 distribution ; and the process of mimetic modification is traced 

 through the female, from the amazing instability of that sex of 

 H. bolina (local form) in the Fiji Islands, where the male is 

 stable and of the normal ancestral pattern and colouring, to the 

 opposite extreme in Africa, where (with the exception of H. 

 misippus) both sexes of the known allied forms of the genus 



