1. It has already been observed that the male insects are less than the female, and that the male mounts upon the female; and the manner of their sexual intercourse has been described, and the difficulty of separating them. Most of them produce their young very soon after sexual intercourse. All the kinds except some psychæ (butterflies and moths) produce worms. These produce a hard substance, like the seed of the cnecus,[168] which is fluid within. From the worm an animal is produced, but not from a portion of it, as if it were an ovum, but the whole grows and becomes an articulated animal. [168] Cantharus tinctorius, a plant of the thistle kind. L. and S. 2. Some of them are produced from similar animals, as phalangia and spiders from phalangia and spiders, and attelabi,[169] locusts, and grasshoppers. Others do not originate in animals of the same species, but their production is spontaneous, for some of them spring from the dew which falls upon plants. The origin of these is naturally in the spring, though they often appear in the winter, if fine weather and south winds occur for any length of time. Some originate in rotten mud and dung; and others in the fresh wood of plants or in dry wood; others among the hair of animals, or in their flesh, or excrements, whether ejected, or still existing in the body, as those which are called helminthes. [169] The larva of some species. 3. There are three kinds of these, the flat worms, the round worms, and those which are called ascarides. From these creatures nothing is produced; but the broad worm is attached to the intestine, and produces something like the seed of the colocynth, and this is used by physicians as a proof of the presence of the worm. 4. Butterflies are produced from caterpillars; and these originate in the leaves of green plants, especially the rhaphahus, which some persons call crambe. At first they are smaller than millet, afterwards they grow into little worms, in three days they become small caterpillars, afterwards they grow and become motionless, and change their form. In this state the creature is called chrysalis. It has a hard covering, but moves when it is touched. They are united to something by weblike processes, and have no mouth nor any other visible organ. After a short time the covering is burst, and a winged animal escapes, which is called a butterfly.