OF SELBORNE. 213 
Sand-martins differ from their congeners in the 
diminutiveness of their size and in their colour, 
which is what is usually called a mouse colour, 
Near Valencia, in Spain, they are taken, says 
Willoughby, and sold in the markets for the table, 
and are called by the country people, probably 
from their desultory, jerking manner of flight, Pa 
pillon de Montagna (the mountain butterfly). 
LETTER XXII. 
Selborne, Sept. 28, 1774. 
Dear Sir,—<As the Swirt or black martin is the 
largest of the British hirundines, so it is undoubt- 
edly the latest comer. For I remember but one 
4 SSS 
instance of its appearing before the last week in 
April; and in some of our late, frosty, harsh 
springs, it has not been seen till the beginning of 
ay. This species usually arrives in pairs. 
The swift, like the sand-martin, is very defective 
in architecture, making no crust or shell for its 
nest, but forming it of dry grasses and feathers, 
very rudely and inartificially put together. With 
