sect, ix.] INTRODUCTION. 53 



are comparatively rare. Butler suggests that these intermediate forma 

 should be regarded as hybrids, even in the absence of experimental 

 evidence. This view is of course dependent on the truth of the belief 

 that such a discontinuous occurrence of variations is anomalous.] 



Twenty specimens of the species T. bethesaba and thirty-nine of 

 T. jaegeri (both from Japan), were also examined. The former pre- 

 sented no variations whatever, and the latter only vary in the yellower 

 or redder tint on the under surface of the secondaries. Butler, A. G., 

 Trans. Ent. Sob, 1880, p. 197, PL vi. 



Compare the following : 



Terras constantia. Twenty-five pupae, all found together on the same 

 twigs at Teapa, Tabasco, Mexico, by Mr H. H. Smith. The butterflies 

 from these are in Messrs Godman and Salvin's collection, who kindly 

 allowed me to examine them. The amount of black border on both wings 

 varies much, nearly though not quite so much as in the cases figured 

 by Butler. In the lightest the apex of the fore-wing alone is black, 

 and there is no black on the hind-wing in 9 specimens ; of the remaining 

 16 some have a well-defined black border to the hind-wing, while in 

 the rest (about 6) this border is slight. This case is a particularly 

 interesting one, as the specimens were associated and presumably 

 belonged to one brood. 



ev 



For another beautiful case of discontinuous Variation in 

 pattern I am indebted to Dr D. Sharp. The Cambridge Univer- 

 sity Museum lately received a series of 38 specimens of Kallima 

 inachys, the well-known butterfly whose folded wings resemble a 

 dead leaf with its mid-rib and veinings. The underside of this 

 butterfly is sometimes marked with large blotches and flecks of 

 irregular shape, which, as has often been noted, resemble the 

 patches of discoloration caused by fungi in decaying Leaves. 

 Dr Sharp pointed out to me that the specimens examined fell 

 naturally into four groups according to the coloration of the 

 underside. In the first group the field is nearly plain, though 

 the tint varies in individuals. The "mid-rib" is strongly marked 

 in this and all the groups, but the "veinings" are absent or very 

 slightly marked in the first group : 18 specimens. In the second 

 group the ground is almost plain, but it bears numerous strongly 

 marked black-speckled spots, of forms which though irregular in 

 outline are closely alike, and occupy the same positions in all the 

 six specimens, being scarcely if at all represented in any of the 

 others. In the third group the dark bars representing "veins' 

 are strong, but the field is nearly uniform : 10 specimens. In the 

 fourth group, of four specimens, the ground-colour is darkened in 

 such a way as to leave large and definite blotches of light colour 

 in particular places. Of these specimens three have the veinings 

 very strongly marked, while the fourth is without them. 



Into these four groups the specimens could be unhesitatingly 

 separated, though in each group many individual differences 



