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4 
THE NATURAL HISTORY OF SELBORNE. Cree wt Ue Og 
in the south seas, near Guayaquil, are desolated, it seems, by 
the infinite swarms of venomous mosquitoes, which fill the air, 
and render those coasts insupportable. It would be worth 
inquiring whether any species of A/irundines is found in those 
regions. Whoever contemplates the myriads of insects that 
sport in the sunbeams of a summer evening in this country, 
will soon be convinced to what a degree our atmosphere would 
be choked with them were it not for the friendly interposition 
of the swallow tribe. 
Many species of birds have their peculiar lice; but the 
fTirundines alone seem to be annoyed with dipterous insects, 
which infest every species, and are so large, in proportion to 
themselves, that they must be extremely irksome and injurious 
to them. These are the Hipfobosce hirundines (bird-ticks), with 
narrow subulated wings, abounding in every nest; and are 
‘hatched by the warmth of the bird’s own body during incuba- 
tion, and crawl about under its feathers. 
A species of them is familiar to horsemen in the south of 
England under the name of forest-fly; and to some of side-fly, 
from its running sideways like a crab. It creeps under the 
tails, and about the groins, of horses, which, at their first 
coming out of the north, are rendered half frantic by the 
tickling sensation ; while our own breed little regards them. 
The curious Réaumur discovered the large eggs, or rather 
pupa, of these flies as big as the flies themselves, which he 
hatched in his own bosom. Any person that will take the 
trouble to examine the old nests of either species of swallows 
may find in them the black shining cases or skins of the pupe 
of these insects; but for other particulars, too long for this 
place, we refer the reader to the “ History of Insects” of that 
admirable entomologist. 
