( xcvi ) 



two forms certainly occur in copuld* But if this evidence 

 were wanting there would still be strong presumptive evi- 

 dence that the forms are associated by syngamy and synepigony. 

 Thus, so far as our knowledge extends, dorippus occurs as the 

 only form in certain parts of N.E. Africa alone. From this, 

 its metropolis, dorippus spreads on all sides, its individuals 

 existing intermingled with those of clirysippxis, becoming less 

 and less numerous until they finally die out. Thus if we 

 trace the two forms eastward we find them both abundant 

 at Aden; further east, at Karachi, dorippus is well known, 

 but very scarce as compared with chrysippus ; in Southern 

 India it is a great rarity, if indeed it is known at all on the 

 mainland ; in Ceylon a single specimen was captured by Col. 

 Yerbury in 1891, and since then others have been taken, f 

 Further east I have never heard of a specimen. Similarly 

 when it is traced southwai-d in Africa, dorippus is dominant 

 in the coast strip of British East Africa, where it constitutes 

 about three-quarters of the total number of individuals. 

 Further to the south it becomes rarer and rarer, until in 

 Natal and the Cape, if it occurs at all, it is even rarer than 

 in Ceylon. J Such a distribution is consistent with the inter- 

 pretation that dorippus and chrysippus are two forms in one 

 syngamic community. It is difl&cult on any other hypothesis 

 to account for the facts which we observe on the outskirts of 



* Speaking of his experience at Aden, Col. Yerbury says: "I have 

 taken them [the forms of chrysippus] in coitu in every possible com- 

 bination." (Journ. Bomb. Nat. Hist. Soc, vii (1892), p. 209.) 



t See Major N. Mandcrs, F.Z.S., in Journ. Bomb. Nat. Hist. Soc. xiv 

 (1902), p. 716 :— 



"The first specimen of this insect [dorippus =klugii] in Ceylon was 

 captured by Lieut. -Colonel Yerbury at Trincomalie, April 15th, 1891 . . ." 

 Of live or six more recent examples Major Manders writes, " These speci- 

 mens were captured by Mr. Pole at Puttalam on the east coast and Ham- 

 bantotte on the south coast in the dryest and perhaps most arid portion of 

 the island. It is evidently widely distributed in the desert portion of the 

 island and is possibly not uncommon." 



" The distribution of this insect in India cannot yet be fully known ; it 

 is rare in Canara, but is not yet reported from the plains of the Deccan, 

 or Southern India, so far as I am aware, though it probably exists." The 

 occurrence of f?or?^^wt.s at Bombay, Kutch, and Sind had been previously 

 published by Major Manders and the late Mr. de Niceville in Journ. As. 

 Soc. Bengal, voL Ixviii, Ft. ii, No. 3, 1899, p. 170. 



X Mr. Roland Trimen tells me that he knows of only three South- 

 African dorippus : — two from Durban and one from Pretoria. The latter 

 and one of the former were taken by Mr. W. L. Distant (Ann. Mag. Nat. 

 Hist. (7), vol. i, 1898, pp. 48, 49). 



