Chap. XIV.] OCELLI. 127 



(Gyrianisa Isis), allied to 6ur Emperor moth, in which a 

 magnificent ocellus occupies nearly the whole surface of 

 each hinder wing ; it consists of a black centre, including 

 a semitransparent crescent-shaped mark, surrounded by 

 successive ochre-yellow, black, ochre-yellow, pink, white, 

 pink, brown, and whitish zones. Although we do not 

 know the steps by which these wonderfully-beautiful and 

 complex ornaments have been developed, the process at 

 least with insects has probably been a simple one ; for, as 

 Mr. Trimen writes to me, " no characters of mere marking 

 or coloration are so unstable in the Lepidoptera as the 

 ocelli, both in number and size." Mr. Wallace, who first 

 called my attention to this subject, showed me a series of 

 specimens of our common meadow-brown butterfly (JSip- 

 parchia Janira) exhibiting numerous gradations from a 

 simple minute black spot to an elegantly-shaded ocellus. 

 In a South African butterfly (Cyllo Leda, Linn.) belong- 

 ing to the same family, the ocelli are even still more vari- 

 able. In some specimens (A, Fig. 52) large spaces on 

 the upper surface of the wings are colored black, and in- 

 clude irregular white marks ; and from this state a com- 

 plete gradation can be traced into a tolerably perfect (A 1 ) 

 ocellus, and this results from the contraction of the irreg- 

 ular blotches of color. In another series of specimens a 

 gradation can be followed from excessively minute white 

 dots, surrounded by a scarcely visible black line (B), into 

 perfectly symmetrical and large ocelli (B 1 ). 46 In cases like 

 these, the development of a perfect ocellus does not re- 

 quire a long course of variation and selection. 



45 This woodcut has been engraved from a beautiful drawing, most 

 kindly made for me by Mr. Trimen ; see also his description of the won- 

 derful amount of variation in the coloration and shape of the wings of 

 this butterfly, in his 'Rhopalocera Africae Australis,' p. 186. See also 

 an interesting paper by the Rev. H. H. Higgins, on the origin of the 

 ocelli in the Lepidoptera in the ' Quarterly Journal of Science,' Julj; 

 1868, p. 325. 



