[40] 



This is a specially interesting series. Nos. 5 and 9 are greyish in colour, 

 moderately well speckled with brown. No. 5 is slightly darker than No. 9 

 at the broad end, but they fit in well as a pair with the general theory of 

 common parentage. No. 16 is an egg of a different type, smaller in size 

 and pale bluish-green with regularly distributed small grained brownish 

 speckling. It is probably the egg of a separate bird. On comparing it with 

 the eggs of series X., from the same area and of same year's taking, 

 and particularly with H 14 and H 15 which were found about the 

 same time (24th and 29th June), we still find this egg distinctive. 

 Whilst it approaches these two more nearly in appearance, its ground 

 colour is of a deeper blue and the amount of brown speckling is rather 

 greater. It is also a smaller egg. 



Xlll. — Tvjo eggs, taken at West Drayton {Bank of Colne) Middlesex. 

 Museum No. Foster. Date when taken. 



M 6/14 . . . Eeed Warbler . . .1st July 1912 

 M 15/5 . . . Sedge Warbler . . . 11th July 1912 



Tliese eggs are of a pale, sandy colour, with light brown speckling 

 running in places into fairly large blotches. The brown colouring is 

 moderately sparse, generally, and absent at the narrow end of the egg 

 which is rather pointed looking. The resemblance of the two eggs is rather 

 striking, and they are probably the offspring of the same bird. Two foster 

 species are involved. 



When single eggs of the foregoing thirteen series taken at random are 

 placed alongside, the interesting fact becomes evident that with one 

 exception no two resemble each other, even approximately, as the members 

 of the sets themselves do. Further, a comparison of sets from the same 

 locality, by the method of taking an egg at random from each group, yields 

 eggs readily distinguished by their colour in each case. There are two 

 sets from Budworth Mere, Cheshire, of the same season, and these are 

 quite distinct when laid alongside, the difference being more marked than 

 any verbal description can bring out. 



There are six sets from Huntingdonshire, representing three different 

 years' takings. Sets IX. and XII. are rather alike, but their resemblances are 

 not so great as the members of any of the sets considered in this paper. 

 They constitute the one exception quoted above. The other examples can 

 all be distinguished at a glance from these and from each other. 



What conclusions can be drawn from these facts ? 



