LETTERS ON ENTOMOLOGY. 9 
year 1766, in the month of August, they ap- 
peared in such incredible numbers at Oxford 
as to resemble a black cloud darkening the air. 
One day a little before sunset, six columns were 
observed to ascend from the boughs of an apple 
tree, some in a perpendicular and others in an 
oblique direction, to the height of fifty or sixty 
feet. Their bite was so poisonous that it was 
attended by violent and alarming inflammation, 
and one, when killed, usually contained as much 
blood as would cover three or four square inches 
of wall. 
The poor Laplanders are the most to be pitied i 
they are obliged to live in suffocating smoke, 
either to eat or sleep, and the insects abound 
so much that they cannot breathe without draw- 
ing them in. Reaumur tells us that in some 
parts of France he saw people whose legs 
and arms were so swelled and inflamed with 
gnat-bites, that it was doubtful whether am- 
putation would not be necessary. In the neigh- 
bourhood of the Crimea, the Russian soldiers 
are obliged to sleep in sacks, to defend them 
from the mosquitos ; and even then, many die in 
consequence of mortification produced by the 
bites of these furious and bloodthirsty insects. 
Dr. Clarke, who relates it likewise, says, that in 
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