284 Professor E. B. Poulton on Mimetic Forms of 



cover, at some point in the wide territories between 

 Abyssinia and Zanzibar, females of the Merope-gxow'^ 

 exhibiting stages intermediate between the long-tailed 

 mimetic females of P. antinorii and the entirely tail-less 

 ones of P. ccnea." 



It was reasonable not to attempt to name this primitive 

 variety while it remained as a single example ; but now 

 that it has been discovered in large numbers as one of the 

 female forms oftlie sub-species i^o/y/^Y^^/wf-s, Jordan, on the 

 Kikuyu Escarpment, the case is different. It is one of the 

 most instructive if nut actually the most instructive of all 

 the female forms of dardanus ; and I propose to call it 

 trimcni, in honour of the great naturalist who solved the 

 mystery, and laid a firm foundation for all future work 

 upon the most interesting and complex example of 

 mimicry as yet known throughout the world * 



The sj)ecimen referred to by Mr, Trimen is here repre- 

 sented on a slightly reduced scale on Plate XIX, Fig. 1. In 

 Plate XVIII, Fig. 1, one of the smaller trimcni forms from 

 the Kikuyu Escarpment is represented of about the 

 natural size. Of these there are four in the Hope Depart- 

 ment. Judging from these four specimens the ground 

 colour is sometimes yellow, exactly like that of the male 

 (1), sometimes of a rather j)aler shade (2), and sometimes a 

 little darker (1). 



(a) Occasional occurrence of rudimcniarij " tails " to the 

 hind-ioing of trimeni a7id hippocoon. 



The trimcni form frequently possesses ancestral 

 characters additional to those described in the Presiden- 

 tial Address. The most interesting of these supplies the 

 confirmation of Mr. Trimen's prediction that stages would 

 be found " intermediate between the long-tailed mimetic 

 females of P. antinorii and the entirely tail-less ones of P, 

 cenear The specimen represented on Plato XVIII, Fig. ], 

 is seen to have a small but distinct rudimentary "tail," 

 containing an extension of the third median nervule. 

 This nervule also enters the tail in the male, sliowiug that 

 the rudimentary tail of the female is entirely homologous 

 with that of the other sex. The other three specimens of 

 'polyiro'plius % f. trimeni do not exhibit this feature, but it is 



* It is perhaps unnecessary to say that I allude to the great mono- 

 graph in Trans. Linn. Soc, vol. xxvi, 1870, Pt. Ill, 1869, p. 497. 



