observations of three springs and two autumns, are most punctual
in their return; and exhibit a new migration unnoticed by the
writers, who supposed they never were to be seen in any of the
southern counties.

One of my neighbours lately brought me a new salicaria, which at
first I suspected might have proved your willow-lark,* but, on a
nicer examination, it answered much better to the description of
that species which you shot at Revesby, in Lincolnshire. My bird I
describe thus: 'It is a size less than the grasshopper-lark; the head,
back, and coverts of the wings of a dusky brown, without those
dark spots of the grasshopper-lark; over each eye is a milk-white
stroke; the chin and throat are white, and the under parts of a
yellowish white; the rump is tawny and the feathers of the tail
sharp-pointed; the bill is dusky and sharp, and the legs are dusky;
the hinder claw long and crooked. The person that shot it says that
it sung so like a reed-sparrow that he took it for one; and that it
sings all night; but this account merits further inquiry. For my part,
I suspect it is a second sort of locustella, hinted at by Dr. Derham
in Ray's Letters: see p. 108. He also procured me a grasshopper-
lark.
(* For this salicaria see letter August 30, 1769.)

The question that you put with regard to those genera of animals
that are peculiar to America, viz. how they came there, and
whence? is too puzzling for me to answer; and yet so obvious as
often to have struck me with wonder. If one looks into the writers
on that subject little satisfaction is to be found. Ingenious men will
readily advance plausible arguments to support whatever theory
they shall choose to maintain; but then the misfortune is, every