t 201 ] 
beginning of Odtober ; but have appeared of late 
years, in a confiderable flight, in this neighbourhood, 
for one day or two, as late as November the 3d and 
6th ; after they were fuppofed to h^ve been go-ne for 
more than a fortnight. They therefore withdraw 
with us the iateft of any fpecies. Unlefs thefe birds 
are very Short-lived indeed, or unlefs they do not 
return to the diftridt where they are bred, they mull 
undergo vaft devastations fome how, and feme 
where ; for the birds, that return yearly, bear no 
manner of proportion to the birds that retire. 
Houfe-martins are distinguished from their conge- 
ners , by having their legs covered, with foft downy 
feathers, down to their toes. They are no fongfters ; 
but twitter in a pretty inward foft manner in their 
nefls : are greatly molefted in their nefts by fleas j 
and annoyed by a large dipterous infedf, with nar- 
row Tubulated wings, which crawls about under 
their feathers, and is known by the name of hip- 
pobofea hirundinis : a fpecies of which is familiar 
to horfemen under the name of foreft-fly ; and to 
fome under the name of flde-fly, as it runs. Tide- 
ways like a crab, creeping under the tails and about 
the groins of horfes. 
Thus does all the creation prey upon one another; 
and thefe birds, though infedt-eaters themfelves, are 
diflrefled and tormented by infedts. 
ls T 
I am, dear sir, with the greateft refpedt, 
Your obliged and moft obedient fervant, 
GIL. WHITE. 
Selborne, 
ov. 20, 1773. 
D d 
Vol. LXIV. 
XXVIII. Ex- 
