The records as to the post-embryonic development of Phasmidae are very scanty, but indicate great differences in the length of time occupied by it. _Bacillus patellifer_ is said to moult several times, _Diapheromera femorata_ only twice. This latter species becomes full grown in six weeks, while, according to Murray,[191] _Phyllium scythe_ required fifteen or sixteen months for growth, and did not moult until ten months after hatching; the number of ecdyses in the case of the _Phyllium_ was three. At each change of skin an immediate increase in size, similar to that we have noticed as occurring on leaving the egg, takes place; each limb on being freed becoming about a fourth longer and larger than the corresponding part of the envelope from which it has just been withdrawn. After the second moult of _Phyllium_ the tegmina and wings made their appearance, but remained of very {264}small size until after the third moult, when they suddenly shot out to their full size; they came out of little cases about a quarter of an inch long, and in the course of a few minutes attained their full size of about two and a half inches of length. In the apterous species the difference between the young and adults in external characters is very slight. [Illustration: FIG. 151.—_Ceroys saevissima._ Brazil. (After Westwood.)] Phasmidae are very sensitive to cold; both in North America and Australia their lives are terminated by the occurrence of frost. They are all vegetable feeders, the cannibalism that has been attributed to them by several writers being probably imaginary. They are, however, excessively voracious, so that a pair will destroy a great quantity of foliage; they are consequently in some parts of the world classed amongst injurious Insects. In Fiji and the Friendly Islands, _Lopaphus cocophagus_ eats the cocoa-nut foliage and causes a scarcity of food, so that it becomes a matter of necessity to destroy these Insects. One writer has gone so far as to attribute the occurrence of cannibal habits amongst the inhabitants of some of these islands to the want of food caused by the ravages of this Insect. Some, if not all, of the Phasmidae have the habit of ejecting a stinking fluid, that is said to be very acrid, and occasionally, when it strikes the eye, to cause blindness; this liquid comes from glands placed in the thorax. Some Phasmidae are much relished as food by birds; _Diapheromera femorata_ is sucked by several bugs as well as eaten by birds, and another species is recorded to have harboured Ichneumon-flies in its body without suffering any apparent inconvenience from their presence or from their emergence. Notwithstanding the great amount of food they consume and their want of activity, they produce comparatively few eggs. From twelve to twenty or thirty is frequently mentioned as about the {265}number, but in the case of _Diapheromera femorata_ Riley speaks of upwards of one hundred. These eggs are not deposited in any careful way,