100 Proceedings of the Royal Physical Society. 
IV.—Two eggs, apparently laid by the same bird, taken at Delamere, Cheshire. 
Museum No, Foster. Date when taken. 
F 15/3. : . Sedge Warbler . ; . 2nd June 1912 
F29/1 . .  .. Lesser Whitethroat . . 6th June 1912 
These are pale grey eggs with brown spots. The general impression is 
that of a very uniform lightish coloration, ze. the speckling is very evenly 
distributed. The two eggs are remarkably alike and cannot be distinguished. 
There are two kinds of foster in this case also. 
V.—Three eggs, apparently laid by the same bird, taken at 
Wigglesworth, Yorkshire. 
Museum No. Foster. Date when taken. 
B 16/2 . ; . Willow Wren . : . 23rd May 1910 
Baye oe . Meadow Pipit . . 27th May 1910 
B18/2 . . Spotted Flycatcher. . 28th May 1910 
These show a most marked resemblance to each other. Colour is 
greyish-blue with brown speckling evenly distributed. There are a few 
darker spots of brown, very small but sharply defined. The three eggs 
cannot be distinguished save by these spots, which are of course not 
identical in size or numbers. It is noteworthy, notwithstanding the prob- 
ability of their being the product of the same bird, that each occurred in 
the nest of a separate species of foster. The collector states that “all of 
the three eggs were found close to where water was in abundance, both 
stagnant pools and running.” . 
VI.—Six eggs, taken by the banks of the River Ouse, in Huntingdonshire, 
within a range of half a male. 
Museum Mark. Foster. Date when taken. — 
Cillee: : . Sedge Warbler . 5 . 11th June 1909 
Cl . Sedge Warbler . . 16th June 1909 
Ce ; . Reed Warbler . : . 17th June 1909 
Cx . : . Lesser Whitethroat . . 18th June 1909 
Cw ; . Whitethroat . : . 18th June 1909 
Ch ; : . Hedge Sparrow . . 14th July 1909 
The ground hue of these eggs is of a bluish-grey, with brown speckling 
fairly thickly distributed. The colour contrasts quite noticeably with that 
of the next set, which was taken in the same region but over a wider 
area, and all, with one exception, in the following year. With the exception 
