The pupa[74] of this insect weighs, a little after its change, much heavier than it does in its beetle state; this is also the case with the pupa of the bee and hornet. The latter has been found to weigh ten times as much as the hornet itself; this is probably occasioned by a superabundant degree of moisture, by which these insects are kept in a state of inactivity, which may be compared to a kind of preternatural dropsy, till it is in some measure dissipated; in proportion as this moisture is evaporated, the skin hardens and dries: some days are required to exhale this superfluous moisture. If the skin be taken off at this time, many curious circumstances may be noted; but what claims our attention most is, that the horn, which is so hard in the male beetle when in a state of maturity, that it will bear to be sharpened against a grindstone,[75] in the pupa state is quite soft, and more like a fluid than a solid substance. How long the scene of mutation continues is not known; some remain during the whole winter, more particularly those which quit the larva state in autumn, when a sudden cold checks their further operations, and consequently they remain in a torpid state, without any food, for several months. Some species of the beetle tribe go through all the stages of their existence in a season, while others employ near four years in the process, and live as winged insects a year. [74] Swammerdam’s Book of Nature, p. 144. [75] Mouffet, p. 152. When the proper time for the final change arrives, all the muscular parts grow strong, and are thus more able to shake off their last integuments, which is performed exactly in the same manner as in the passage of the insect from the larva to the pupa state; so that in this last skin, which is extremely delicate, the traces of the pulmonary tubes, that have been pulled off and turned out, again become visible. All parts of the insect, and more particularly the wings and their cases, are at this period swelled and extended by the air and fluids which are driven into them through the arteries and pulmonary tubes; the wings are now soft as wet paper, and the blood issues from them on the least wound; but when they have acquired their proper consistency, which in the elytra is very considerable, they do not exhibit the least sign of any fluid within them, though cut or torn almost asunder. The pupa being disengaged from its skin, assumes a different form, in which it is dignified with the name of a beetle, and acquires a distinction of sex, being either male or female. The insect now begins to enjoy a life far preferable to its former state of existence; from living in dirt and filth, under briars and thorns, it raises itself towards the skies, plays in the sun-beam, rejoices in its existence, and is nourished with the oozing liquors of flowers. OF THE MUSCA CHAMÆLEON.