99 [Vol. xxix. 



types o£ colouring, wliicli might be roughly described as 

 '^blue^' or " gveen/' and " red/^ In some species the 

 ^'red" eggs were so numerous as to constitute the type, 

 while in others they were extremely rare. Among British 

 birds examples in which the " red '^ type was common were 

 the Tree-Pipit (Anthus trivialis) and the Red-backed Shrike 

 [Lanius collurio). As examples of British birds in which 

 the " red " eggs occurred only rarely, the Sedge-Warbler 

 (Acrocephalus phragmitis) , the Common Tern {Sterna hirundo) , 

 and the Lapwing [Vanellus vanellus) might be mentioned. 

 A remarkable characteristic of this peculiarity was the way 

 in which it occurred in certain families. Thus in the Corvidse 

 it had been known to occur in the E-aven (Corvus corax), 

 the Hooded Crow (C comix), the Eook (^C.frugilegus), the 

 Magpie {Pica pica), and apparently also in the Jay {Gar- 

 rulus glandarius), while in the Cape Rook (Corvus capensis) 

 it was found apparently to the exclusion of the " blue " 

 type, and the Choughs {Pyrrliocoi'ax) also showed a strong 

 tendency to a permanently erythristic type. 



Mr. E. BiDWELL suggested that a list of those cases in 

 which erythrism had been recorded should be published in 

 ' British Birds/ in which all the known records should be 

 brought together, and he proceeded to mention instances of 

 erythrism in the Raven and Jay which had come to his 

 knowledge. 



Mr. C. BoRRER mentioned that he had already prepared a 

 tentative list of this kind, supplementing that given by the 

 Rev. F. C. R. Jourdain in the * Proceedings of the 4th 

 Internat. Ornith. Congress ' (1905), pp. 583-593. 



The question then arose as to how far the colour- variation 

 was dependent on locality, and Mr. Jourdain mentioned that 

 though no case of erythrism had been recorded in the eggs of 

 the western race of the Subalpiue Warbler [Sylvia cantillans) 

 from either Corsica or Sicily, Captain Lynes had obtained a 

 large series of red eggs from the south-west of Spain, where 

 it was evidently the prevalent type. Similarly, though no 

 red eggs of the Dartford Warbler had ever been taken in 

 England, the red type was by no means uncommon in fSouth 



