natural history would
have formed an interesting volume; and many a half-hour have I spent
beside it in the heat of the day, watching its numerous
inhabitants--insect, reptilian, and vermiferous. There were
two--apparently _three_--different species of libellula that used to
come and deposit their eggs in it--one of the two, that large kind of
dragon-fly (_Eshna grandis_), scarce smaller than one's
middle-finger--which is so beautifully coloured black and yellow, as if
adorned by the same taste one sees displayed in the chariots and
liveries of the fashionable world. The other fly was a greatly more
slender and smaller species or genus, rather _Agrion_; and it seemed
two, not one, from the circumstance, that about one-half the individuals
were beautifully variegated black and sky-blue, the other half black and
bright crimson. But the peculiarity was merely a sexual one: as if in
illustration of those fine analogies with which all nature is charged,
the sexes put on the _complementary_ colours, and are mutually
fascinating, not by resembling, but by _corresponding_ to, each other. I
learned in time to distinguish the disagreeable-looking larvae of these
flies, both larger and smaller, with their six hairy legs, and their
grotesque formidable vizors, and found that they were the very pirates
of the water, as the splendid insects into which they were ultimately
developed were the very tyrants of the lower air. It was strange to see
the beautiful winged creature that sprang out of the pupa into which the
repulsive-looking pirate had been transformed, launch forth into its new
element, changed in everything save its nature, but still unchanged in
that, and rendering itself as formidable to the moth and the butterfly
as it had been before to the newt and the tadpole. There is, I daresay,
an analogy here also. It is in the first state of our own species, as
certainly as in that of the dragon-fly, that the character is fixed.
Further, I used to experience much interest in watching the progress of
the frog, in its earlier stages from the egg to the fish; then from the
fish to the reptile fish, with its fringed tail, and ventral and
pectoral _limbs_; and, last of all, from the reptile fish to the
complete reptile. I had not yet learned--nor was it anywhere known at
the time--that the history of the individual frog, through these
successive transformations, is a history in small of the animal creation
itself in its earlier stages-