204 Dr. F. A. Dixey on 



the Central African serena and its southern sub-species 

 is that in the former the black band near the apex of 

 the forewing is continuous, but broken in the latter. 

 If I remember right, there is a somewhat similar difference 

 between achcloia and its Central African form goetzius, 

 which, if correct, would further bear out my idea. Now 

 as to the winter form ; the underside of this is of course 

 quite unlike that of any Acrma, and I can only suppose 

 that it is a case of protective resemblance on the principle 

 of the zebra's or tiger's stripes, for the insect always 

 roosts on grass. It is interesting to note however that that 

 part is undergoing modification in the variety acheloia, 

 as the marginal white line in both wings has already done. 

 It would be interesting to know whether there is any 

 likeness between this species and the Indian Acnvas." — 

 G. A. K. M. 



As I have elsewhere stated, I consider that Byhlia 

 gotzius, Herbst, which Mr. Marshall here speaks of as 

 B. ilithyia var. aclidoia, is entitled to distinct specific rank 

 beside B. ilithyia, Drury. Mr. Marshall's ob.servation with 

 regard to the continuity of the apical black band of the 

 forewing in the Central African form of B. gotzius is borne 

 out on an examination of specimens in the Hope collec- 

 tion and the British Museum. It was remarked by me 

 some time since, in discussing the modifications oi B. ilithyia 

 and its allies, that " the Socotran B. hoydi resembles most 

 specimens of B. gotzius from the West African subrogion 

 in having the dark costal bar of the forewing continued 

 rather heavily across the wing to join the submarginal 

 band. This is also more or less the case with two females 

 of B. gotzius from Abyssinia, and specimens of the same 

 from Somaliland and Aden in the British Museum ; but in 

 examples from South and East Africa the connection be- 

 tween the costal and the submarginal dark bands is often 

 slight or absent." * It is worth noting that the marginal 

 white line spoken of by Mr. Marshall, on the under- 

 side of both wings in the dry-season form of B. ilitjiyia, 

 has disappeared from the dry-season B. gotzius, but persists 

 in B. hoydi, of which only the dry-season form is at present 

 known. This is another indication of the intermediate 

 position of the latter insect, which, though nearer to 

 B. gotzius, yet shows several points of resemblance to 

 B. ilitlnjia. 



* Proc. Zool. Soc, 1898, p. 378. 



