GEOGRAPHICAL DISTRIBUTION OF INSECTS. 477 
of plants, 60,000 being already known, may be some- 
where between 110,000 and 120,000?. If we consider, 
with reference to this calculation, that though the great 
body of the mosses, lichens, and sea-weeds are exempt 
from the attack of insects, yet as avast number of phanero- 
gamous plants and fungi are inhabited by several species, 
we may form some idea how immense must be the num- 
ber of existing insects ; and how beggarly does Ray’s con- 
jecture of 20,000 species», which in his time was reckoned 
a magnificent idea, appear in comparison! Perhaps we 
may obtain some approximation by comparing the num- 
ber of the species of insects already discovered in Britain 
with that of its phanerogamous plants. The latter,—and it 
is not to be expected that any large number of species have 
escaped the researches of our numerous Botanists,—may 
be stated in round numbers at 1500, while the British in- 
sects, (and thousands it is probable remain still undisco- 
vered,) amount to 10,000; which is more than szz insects 
to one plant. Now though this proportion, it is probable, 
does not hold universally; yet if it be considered how 
much more prolific in species tropical regions are than 
our chilly climate, it may perhaps be regarded as not 
very wide of a fair medium. If then we reckon the pha- 
nerogamous vegetables of the globe in round numbers at 
100,000 species, the number of insects would amount to 
600,000. If we say 400,000, we shall perhaps not be 
very wide of the truth. When we reflect how much 
greater attention has been paid to the collection of 
plants than to that of insects, and that 100,000 species 
of the latter may be supposed already to have a place 
* Essai Elément. de Geograph. Botan. 62, 
> Wisdom of God, &e, 2d edit. 9. 
