will contribute to their perfeQion, and be acceptable to the
■ feveral appetites o f their young ones. This is beautifully
illufhated by Mr. Brooke, in his philofophical poem on Universal
Beauty, where, fpeaking on this fubjeft, he fays,
Each as refleSing on their primal ftate,
Or fraught with fcientific craft innate,
With confcious (kill their oval embryo filed
Where native firft their infancy was fed :
Or on fome vegetating foliage glued ;
Or o’er the flood they fpread their future brood ;
A Bender cord the floating jelly binds,
Eludes the wave, and mocks the warring winds.
O ’er this therr fperm in fpiral order lies,
And pearls in living ranges greet our eyes.
In firmed oak they fcoop a fpacious tomb,
And lay their embryo in the fpurious womb :
Some flowers, fome fruit, fome gums, or bloflbms chufe,
And confident their darling hopes infufe ;
While fome their eggs in ranker carnage lay,
And to their young adapt the future prey.
* * * * * * * *
* * * * * * * *
All by their dam’s prophetic care receive
Whate’er peculiar indigence can crave :
Profufe at hand the plenteous tables fpread,
And various appetites are aptly fed.
Nolefs each organ fuits each place o f birth,
Einn’d in the flood, or reptile o’er the earth.
Each
M icroscopical E ssays. 271
Each organ apt to each precarious ftate,.
As for eternity defign’d complete..
O f all the productions o f nature, infefts are the moll numerous,
and multiply mo d ; their fecundity is prodigious, their,
multiplication aftonifhing ; the vegetables which cover the furface
o f the earth bear no proportion to their multitudes, every plant
fopporting a number often of fcarce perceptible creatures; of
the fatal effects of their prodigious multiplication, our fruit-trees,
&c; are too often a deplorable teftimony.. On the continent:
whole provinces often languifh in confequence o f the dreadful,
havock made by the minute, but innumerable, hofts o f infeQs..
The following is anexperiment o f M. Lyoneton the generation,
o f a moth which comes from the chenille a brofle: out o f a brood
o f 350 eggs, that he had from a-Angle moth of this kind, he took
80, from which he got, when they were arrived at their perfect
ftate, 1,5 femaltes; from whence he deduces the following com
fcquence: if 80 eggs- give 1,5 females, the whole brood o f 350
would have produced 65 ; thefe 65, in fuppofing them as fertile
as their mother, would, have produced 22,750 caterpillars, among
which there would have been at leaft 4265 females, who would
have produced for the third generation 1,492,750 caterpillars.
This number would have been, much larger if the number o f females
among thofe-which were feleQed by M. Lyonet had been
«Treater. M- de'Geer. counted in the, belly o f a moth 480 eggs,,
reducing thefe to 400, if fuppofing one-fourth only o f thefe to be
females, and as fruitful as their mother, they will give birth to
40,000 caterpillars for the fecond generation; and for the third,
fuppofing all things equal, four millions of caterpillars. It is not
furprizing,