192 
OF INSECTS. 
multitude of species which the microscope discovers, that 
we are struck with w’hat Cicero has called “the insatiable 
variety of nature.” There are said to be six thousand 
species of flies; seven hundred and sixty butterflies; each 
different from all the rest, (St. Pierre.) The same writer 
tells us, from his own observation, that thirty-seven species 
of winged insects, with distinctions well expressed, visited 
a single strawberry plant in the course of three weeks.* 
Ray observed, within the compass of a mile or two of his 
own house, two hundred kinds of butterflies, noctural and 
diurnal. He likewise asserts, but I think without any 
grounds of exact computation, that the number of species 
of insects, reckoning all sorts of them, may not be short 
of ten thousand.t And in this vast variety of animal forms 
(for the observation is not confined to insects, though more 
applicable perhaps to them than to any other class) we are 
sometimes led to take notice of the different methods, or 
rather of the studiously diversified methods, by which 
one and the same purpose is attained. In the article of 
breathing, for example, which was to be provided for in 
some way or other, besides the ordinary varieties of lungs, 
gills, and breathing-holes (for insects in general respire, 
not by the mouth, [PI. XXXIII. fig. 7,] but through holes 
in the sides,) the nymphae of gnats have an apparatus to 
raise their backs to the top of the water, and so take breath 
[PI. XXXIII. fig. 8.] The hydrocanthari do the like by 
thrusting their tails out of the water. J The maggot of the 
eruca labra [PI. XXXIII. fig. 9,] has a long tail, one part 
sheathed within another, (but which it can draw out at 
pleasure,) with a starry tuft at the end, by which tuft, 
when expanded upon the surface, the insect both supports 
itself in the water, and draws in the air which is necessary. 
In the article of natural clothing, we have the skins of ani¬ 
mals invested with scales, hair, feathers, mucus, froth; or 
itself turned into a shell or crust: in the no less necessary 
article of offence and defence, we have teeth, talons, beaks, 
horns, stings, prickles, with (the most singular expedient 
for the same purpose) the power of giving the electric 
* Vol. i. P . 3. 
t Wisdom of God, p. 23. The number of species of insects known 
to entomologists, and preserved in cabinets, is at present not less than 
forty thousand. This number, however, must probably form a small 
proportion of the whole number which exist upon the earth.—See Kirly 
and Spence's Entomology. —Ed. 
t Derham, p. 7 
