Adam Sedgwick

“ The most familiar examples of metamorphosis are the abrupt changes which occur at the end of the larval history of the frog and of many insects. In both these cases there is a sudden and great change of environment; there is a sudden demand for new organs which would have been quite useless in the old environment, and organs which were of use in the, old environment and are of no use in the new have to be eliminated. The two examples we have chosen have the advantage of showing us the two methods by which the crisis in the life-history is met. ”

“ The Insect has no power of recognising a cell that has been previously pierced either by itself or by another of its species. One bee larva can only supply nourishment for a single larva of the parasite, and yet it is a common occurrence for a cell to be revisited, pierced again and another egg introduced; indeed Fabre, by means of the cells he had marked, was able to assure himself that it is no uncommon thing for this to be done four times; four eggs, in fact, are sometimes deposited in a cell that cannot by any possibility supply food for more than one larva. ”

“ Mallock has described many beautiful scenes in his book, but I think he could have found few more beautiful than this old garden with its deserted gardener's house, now a heap of ruins, but overgrown with masses of luxuriant vegetation, with beautiful flowers peeping out here and there as if charitably endeavouring to hide the negligence of man, and to turn the desolation into a scene of beauty. ”

“ If this happens before it has approximately acquired the adult form, it is called a larva (Lat. larva, ghost, spectre, mask) , and the subsequent development by which the adult form is acquired constitutes the larval phase. In such forms the life-cycle is divided into three phases, the embryonic, the larval and the adult. The transition between the first two of these is always abrupt; whereas the second and third, except in cases in which a metamorphosis occurs (see Metamorphosis) , graduate into one another, and it is not possible to say when the larval stage ends and the adult begins. ”

“ A very simple calculation will show how favourable some of the chief features of Insect life are. Let it be supposed that growth of the individual takes time in proportion to the bulk attained, and let A be an animal that weighs one ounce, B a creature that weighs ten ounces, each having the power of producing 100 young when full grown; a simple calculation shows that after the lapse of a time necessary for the production of one generation of the larger creature the produce of the smaller animal will enormously outweigh that of its bulkier rival. ”

“ The structure of the outer skeleton, or external part of the body, exhibits some peculiarities, the chief of which is the detachment of the side-pieces of the prothorax and their great development. Not less remarkable is the abstraction of a segment from the abdomen to become, as it were, part of the thorax; while between the first and second true segments of the abdomen there exists a joint, or articulation, of the utmost mechanical perfection, enabling the operations of stinging and piercing to be executed with an accuracy that cannot be surpassed. ”

“ It is rare to find the post-embryonic development of an Insect occupying so long a period, so that we are justified in saying that brief as may be the life of the may-fly itself, the period of preparation for it is longer than usual. Réaumur says, speaking of the winged fly, that its life is so short that some species never see the sun. Their emergence from the nymph-skin taking place at sunset, the duties of the generation have been, so far as these individuals are concerned, completed before the morning, and they die before sunrise. ”

“ Astonishing as may be the rapidity of the physiological processes of Insects, the results attained by them are, it must be admitted, scarcely less admirable: the structures of the Insect's body exhibit a perfection that, from a mechanical point of view, is unsurpassed, while the external beauty of some of the creatures makes them fit associates of the most delicate flowers or no mean rivals of the most gorgeous of the feathered world. The words {85}of Linnaeus, "Natura in minimis maxime miranda," are not a mere rhetorical effort, but the expression of a simple truth. ”

“ Termitidae belong to the division of Insects in which the wings are developed outside the body; Hymenoptera to the division in which they are developed inside the body. In Termites the growth of the individual is slow, and the final form is reached gradually. In the ants the growth is carried on with great rapidity, and during it the Insect is a helpless maggot absolutely dependent on the attentions of its seniors, while the difference in form and structure between the ant-larva and the ant are enormous. Both anatomy and ontogeny are profoundly different in ants and Termites. ”

“ One of the most remarkable of the features of Orthoptera is that a great difference frequently exists between the colours of the tegmina and of the wings, i.e. the front and hind wings; the latter are concealed in the condition of repose, but when activity is entered on and they are displayed, the individual becomes in appearance a totally different creature. In some cases, contrary to what usually occurs in Insects, it is the female that is most remarkable; the male in Mantidae and Phasmidae being frequently a creature of quite inferior appearance and power in comparison with his consort. ”

“ Why does the larva grow up to a certain period with great rapidity, then cease its appropriating power and break up the parts that have been so rapidly and recently formed? And why do the imaginal buds remain quiescent till the other tissues are being disintegrated, and then, instead of sharing the general condition of disintegration, commence a career of development? ”

“ In the waters of the globe the predominance of Insect life disappears. In the smaller collections of fresh water many Insects find a home during a portion of their lives, and some few contrive to pass their whole existence in such places; but of the larger bodies of fresh water they invade merely the fringes, and they make only the feeblest attempt at existence in the ocean; the genus Halobates containing, so far as we know, the sole Insects {84}that are capable of using the ocean as a medium of existence at a distance from the shore. ”