30 



rnocEEDixos or thk 



feinal(! (Ja/>i<t, and tlie ])atteni of botli was strongly inherited by 

 the dnhia forms amo!ig the offspring*. 



Tlie second exain|)le is Hypolimnas dinarclia, of which 

 Mr. Lamborn bred two large families from known female parents. 

 In one of these the white of the hind wing is faintly tinged with 

 yellow and there is a very slight difference in the pattern of the 

 fore wing. There is a strong tendency towards the inheritance 

 of both these features by the female offspring t- 



d. Ilereditarij Transmission of Small Variations in the Hippocoon 

 Female of the African Papilio dardanus. 



The inheritance of small variations in the pattern of the black 

 and white hi^^pocoon females of Papilio dardanus has been care- 

 fully studied by Dr. (x. D. H. Carpenter J, who has shown that a 

 single small spot in the fore-wing cell differs in size in various 

 parts of Africa and also that slight differences in this and other 

 features bet\\een the females in the same locality are inherited by 

 their hippocoon offspring. Some of these differences are excellent 

 examples of small steps that would lead towards the trans- 

 formation of the hippocoon pattern characteristic of one part of 

 Africa to that which, under the influence of a slightly different 

 model, is characteristic of another part §. Dr. Carpenter's paper 

 is a complete answer to the contention that, in no clear case, has 

 the inheritance of any small variation been shown to exist \\. 



II. Indirect Evidence of Hereditary Transmission of 

 Local Difference. 



a. Tlie V-Marlc on the Hind Winn of the Danaine Genus 

 Tirumala. — I now propose to consider certain indirect evidence of 

 the liereditary transmission of small variations. Of this an 

 unlimited amount is yielded by a study of the geographical 

 changes in the patterns of related groups of species or subspecies. 

 In passing from one locality to another across the total range we 

 are constantly made aware of extremely minute progressive 

 differences only to be reasonably explained by the gradual dis- 

 ap[)earance or moditication of a relatively ancestral feature highly 

 developed or differently developed in some other part of the 

 common area of distribution. When at some widely separated 

 locality the progressive changes first culminate in the disappear- 

 ance of the feature, this climax of modification may only be found 

 in relatively few individuals, the others still retaining traces 

 varying from a few scales or even a single scale up to a small but 

 dist^inct representation. A little furtlier and the proportion of 

 entire disappearances increases while the size of the maximum 

 representation deci'eases. Thus by progi'essive changes in the 

 average constitution of the mass of individuals in successive 



* Recorded in Bedrock, Apr. 1913, p. 56, plate iii.; Oct. 1913, pp. 299, 300. 

 + Bedrock; Oct. 1913, p. 300. 

 \ Trans. Ent. Soc. Lond., 1913, p. 6.")6. 



§ Tlie sigiiifii-anco of one of tlios*; hereditarj' features was poiuted out by 

 (lie iiri'sent writer in Bcdroc/c, Apr. 1913, p. 50. 



II rrolessor Puniictt in Bedrock, July 1913, pp. 152, 153. 



