498 MR. TRIMEN ON MIMETIC ANALOGIES AMONG AFRICAN BUTTERFLIES. 



view propounded by Mr. Bates has met with the weighty support of Mr. Wallace, who, 

 in his interesting paper on Malayan PapiUonidce'^ , has called attention to an analogous 

 series of phenomena presented in India and the great Eastern Archipelago, and can 

 only account for them on the same theory. 



My object in the present paper is to give some account of the most striking cases of 

 mimetic analogy which have been found to exist among the Butterflies of Africa, more 

 especially regarding those occurring at the southern extremity of the continent, a region 

 in which I have had the advantage of several years' personal research. 



In the first place, it is eminently worthy of remark that the Butterflies which are the 

 subjects of imitation by others, belong to the same families both in the Old World and 

 the New. The Danaidce and AcneidcB, throughout the warmer parts of the earth, are 

 unquestionably the special groups that furnish the models after which more or less 

 perfect copies have been elaborated. This being an acknowledged fact, we are naturally 

 led to inquire why it should be so — what advantage is to be gained by closely resembling 

 the members of those families. Is there anything connected with those groups tending 

 to show that they possess advantages above others of their Order ? Do they appear, 

 from their numbers and habits of life, to be dominant races ? 



These inquiries can unhesitatingly be answered in the aifirmative. The slow flight, 

 the conspicuous colours, the complete disregard of concealment, no less than the great 

 abundance of individuals, are characteristics indicating unmistakably that these Butter- 

 flies are favoured races, enjoying advantages and immunities above their fellows. I 

 believe that Mr. Bates {loc. cit. p. 510) has correctly suggested the principal causes of the 

 evident security of these insects, viz. their emitting an unpleasant odour, and being proba- 

 bly distasteful to insectivorous animals. The peculiar smell noticed by Mr. Bates in the 

 Heliconide Dcmaidce is also possessed by the EuplcecB of the Eastern Archipelago, as Mr. 

 Wallace has recorded ; and I am enabled to add similar evidence as regards the African 

 species of Danais and Acrcea-\. Judging from the case of Acrcea Sorta, a widely- 

 distributed African species, which I have reared in considerable numbers from the young 

 larvfB, this disagreeable smell is not peculiar to the imago condition, but attends the insect 

 throughout its life, even the pupae emittmg it. On pressing the thorax of a Danais, 

 a Euplcea, or an Acrcea, however lightly, a clear yellow liquid, similar to that secreted 

 by the Ladybii-d beetles, almost always exudes from that part of the body ; and in some 

 species of the two former genera a pair of bright-yellow fascicled appendages are protruded 

 from the extremity of the abdomen J. The peculiar scent appears chiefly to reside in 

 this liquid, being remarkedly stronger with each effusion. Most of the species of Danais 

 and Acrcea feign death very readily ; and they possess another means of defence which, 

 as far as I am aware, has not hitherto been recorded, viz. the remarkable elasticity of 

 their entire structure. No pressure of the thorax, short of absolute crushing of the 

 tissues, sufiices to kill or even paralyze these Butterflies ; and the collector who treats 



* Traus. Linn. Soc. vol. xsv. 



t The Mauritian Euplcea Euphone also gives out a strong odour when handled. 

 I Mr. Bates mentions that species of the genera Lijcorea and Itmia (Heliconide Danakhi') possess similar exsertile 



