The legs are composed of five parts, each having a separate name. The first piece or joint, which is that attached to the body, is called the hip, or coxa; the next is a very small, somewhat triangular piece, and is the trochan´ter; next comes the long and stout thigh, or fémur; this being succeeded by the tib´ia, which, as in most insects, is furnished with strong spines at the end; and lastly is the foot, or tar´sus, consisting of five joints, the three last of which are represented in the figure (Pl. X. fig. 32). At the end of the fifth or last joint of the tarsus (fig. 32) (for it must be noted that the joints of the limbs of insects are always numbered in order of distance from the body) are two soft little cushions, or pulvil´li, which are covered on the under surface with numerous hair-like bodies dilated at the end, acting as suckers in enabling the fly to adhere to smooth surfaces. In addition to these organs are two curved claws, and between them a sharp straight spine. The eggs of the fly are deposited upon heaps of decaying animal and vegetable matters, as dungheaps, &c. The blow-fly deposits its eggs in the same situations, but especially those where the animal matters are most abundant: every one knows the eggs as deposited upon tainted meats, when they are called flyblows. When the eggs are hatched, the _larvæ_ or maggots make their appearance. The larvæ of the blow-fly are well known to the angler, who uses them for bait, and calls them gentles. These larvæ exhibit some interesting points of structure. The jointed or ringed condition of the body is distinct to the naked eye. The head is provided with two rudimentary palpi, placed each upon a rounded papilla; also with two brown curved and horny hooks or jaws. On the posterior end of the body are two brown spots, which consist of spiracles, and have three sieve-like oblong orifices; and at the anterior margin of each segment of the body are very numerous little short spines, with the points directed backwards. These answer the purpose, to some extent, of legs; for when the larva is moving, and has forced itself through the matter in which it burrows, the little spines prevent the body being forced backwards as the head is pushed forwards and meets any resistance. To examine the structure of these larvæ, the gentles should be killed by immersion for a time in warm water, and then dried by touching them with blotting-paper. The hooks and palpi can be seen by holding the body in the forceps as an opake object. To observe the spiracles, the end of the body should be cut off, and the animal matter washed away in a watch-glass with water and a hair pencil, then spread out, dried between two slides, and mounted in balsam.