820 INSECTA. 
the plants upon which they feed, Decandolle conjectures, that sixty thousand 
species being already known, the total number of plants may extend from 
one hundred and ten thousand to one hundred and twenty thousand. And 
Messrs Kirby and Spence, reasoning on this calculation, and that several 
insect inhabitants are often found upon the same plant, conjecture that four 
hundred thousand insect species may exist on the surface of the globe: and, 
proceeding on the same data with regard to the plants of that country, that the 
insects indigenous to Great Britain may be estimated at ten thousand. In- 
cluding the Arachnides and Crustacea, one hundred thousand species arc 
computed already to have a place in cabinets. 
The slow progress of the science of entomology has left to be discovered 
by future inquirers, many of the uses of insects in the economy of nature. 
From what is known, however, of certain races, the analogical inference, 
regarding the whole, may be deduced, as equally proofs of Divine wisdom 
and beneficence. Myriads of these small and incessant workers, by their 
_feeding on dead, decayed, or excrementitious matters, not only preserve the 
atmosphere in purity, but themselves enjoy the blessings of existence. 
Some furnish an agreeable food, and others are employed in medicine and 
the arts. Many form the chief or only subsistence of quadrupeds, birds, and 
reptiles, and the silk-worm furnishes one of the most beautiful materials of 
dress. It has been remarked that from the study of entomology, many use- 
ful arts might have been derived. Thus the hornets composed their dwell- 
ing of a species of paper, long before the manufacture of that invaluable 
article was stumbled on by human ingenuity; the Tenthredines or saw-flies, 
cut the branches of trees with their serrated instruments, long before the use 
of the saw was discovered in the arts; and their small but powerful instru- 
ment has still this advantage over the mechanic’s tool, that it combines the 
properties of a rasp and file, along with that of a saw. The wood-boring 
bee and the ichneumons are possessed of an apparatus for boring, from 
which even human ingenuity may improve their implements destined for 
similar purposes. A small animal of the size of the common ant, (the 
termes,) builds in an incredibly short space of time, in Africa and Asia, a 
dwelling of fifteen or sixteen feet in height, upon which the pick-axe makes 
no impression; and finally, the organs with which the butterflies, the culices, 
and the common flies pump up the juices upon which they feed, might pos- 
sibly afford hints for improvement in instruments used for a similar purpose 
in the arts. “‘ These animals,” says Latreille, “are often so minute, that one 
cannot even discover their forms without the aid of the microscope; but to 
the eye of the philosopher, the mass or volume of an object is a matter of 
little consequence. The wisdom of the Creator never appears with more effect 
than in the structure of those minute beings, which seem to conceal them- 
selves from observation, and Almighty power is never more strikingly ex- 
lubited than in the concentration of organs in such anatom. Mn giving life 
to this atom, and constructing in dimensions so minute, so many organs, 

