Another interesting example, though not so striking as the last, is to be found in the case of a group of moths known as the Liparidæ. The caterpillars of these are remarkable for their very hairy bodies, often ornamented by several bold brush-like tufts. The chrysalides are also hairy; and several of the moths themselves are not only thickly clad with shaggy hair, but a bold tuft often tips the abdomen.

      We must not leave these few remarks on the characters of chrysalides without a mention of the brilliant spots of burnished gold that decorate the pupæ of certain butterflies. This is the feature that led to the invention of the term chrysalis, which is derived from the Greek word chrysos, meaning gold. For the same reason the term aurelia has been applied to the pupæ of Lepidoptera, this being derived from aurum– the Latin name for gold.

      Strictly, then, these two terms apply only to the pupæ of a certain number of the butterflies; but the former is now generally used to designate the pupæ of all the Lepidoptera, and is even extended to the corresponding stages of insects of other orders.

      If you examine one of these gold-speckled chrysalides, the brilliant metallic lustre seems to belong to the outer surface, just as if certain spots had been tipped with real gold; but after the butterfly has quitted its case the beautiful golden spots are gone. This proves that the metallic appearance is not due to reflection from the outer surface of the chrysalis, but to a reflection from some structure beneath it. This latter is a very thin membrane which lies just under the outer transparent covering of the chrysalis.

      The period during which the Lepidoptera remain in the chrysalis state varies very considerably in different species, and also depends more or less on the temperature. As a rule, when a caterpillar pupates before the end of the summer, it remains dormant in the pupal condition for only a few weeks; but, if late in the summer or in the autumn, it remains in this condition throughout the winter, and emerges in the following spring or early summer.

      Both these conditions are illustrated in the life history of the Large White or Cabbage Butterfly – an insect with which we have already become acquainted. We get two distinct broods of this butterfly every year, the first appearing in May and the second in August. The eggs of the first brood hatch in about a fortnight, and the larvæ are full grown about four weeks later. These then change to chrysalides, from which the perfect insects (the second brood) emerge in a few weeks – the period varying slightly with the temperature of the season. From the eggs of this second brood we get another invading army of cabbage eaters that change to pupæ late in the summer. These remain dormant till the following April, and may be found in numbers throughout the winter, attached to the walls and fences of kitchen and market gardens.

      If, then, the pupæ of the same species are so influenced by the temperatures of the seasons, can we limit or prolong the period of quiescence by subjecting them to high or low temperatures artificially produced? Most certainly we can; and every practical entomologist knows how to obtain the perfect butterflies and moths of certain species long before their appointed times, or, if he desires it, to compel them to remain in their dormant stage long after the natural period has terminated.

      Sometimes an enthusiastic insect hunter obtains a large number of what we may term 'winter pupæ,' by collecting and breeding various species. He also anticipates a number of successful captures of perfect insects during the following summer. Thus, from two distinct sources, he obtains a goodly assortment of butterflies and moths, the setting, preserving, and arranging of which entails an immense amount of home work.

      Under such circumstances he will sometimes endeavour to cause some of his pupæ to emerge before their accustomed time, so that he may get some of his insects 'on the boards' before his field work is in full swing, and so avoid a rush, or prevent the loss of insects that will be spoiled before he has time to take them in hand.

      This process of hurrying up his pupæ he calls 'forcing,' and simply consists in keeping them for a time in a warm room or hothouse where the high temperature is pretty constant.

      On the other hand, the entomologist may desire to try the effect of a continued low temperature on his pupæ. This he can do by placing his pupæ in an ice house. Such experiments have often been performed, and the results are very interesting. In some cases the emergence of the perfect insect has been delayed for many months, and even years; and then, after an exposure to a normal temperature lasting only a week or two, the winged insect has made its appearance just as if nothing unusual had happened.

      Such are the effects of extreme temperatures on the duration of the chrysalis state; and we naturally infer, from such results, that the pupa under natural conditions is influenced, though in a lesser degree, by the variations experienced with the seasons, especially in such a fickle climate as our own.

      The insect hunter has always to bear this in mind, and particularly so when he sets out on a search for certain desired species. Suppose, for example, he has set his mind on the capture of a certain butterfly that usually appears in the first week in May. Before finally naming the day, he has to consider what the weather has been during the last few weeks, and if he finds that this has been much warmer than the average for the corresponding periods in the past, he selects a day in April, earlier or later according to the difference between the present season and the average.

      If he does not pay due attention to such considerations, he will sometimes find that all the insects netted are shabby and much worn, even though, under average conditions, he would be catching newly emerged and brilliant specimens. This, then, will explain how it is that we so often see in entomologists' periodicals startling accounts of 'early captures,' and of the appearance of certain insects late in the season that ought not to have emerged till the following summer.

      I will give just one illustration of these variations. The beautiful Orange Tip Butterfly (Plate I, fig. 7) generally appears about the middle of May in the southern counties. Farther north it is of course a little later. In the north of England it has been taken in June; and in Scotland as late as July. On the other hand, I have taken it in Gloucestershire as early as March, on a rather bleak day with a cold east wind; and, withal, in a field on the slope of the Cotswolds fully exposed to the unfavourable breeze; but it was evident that, in this case, the butterfly had been enticed from its winter quarters by the milder weather of the few previous weeks.

      It may be as well, in passing, to observe that it is not only the pupa that is influenced by temperature. The hatching of eggs may be forced by high temperatures, or be retarded by exposure to cold; and in nature the period of incubation varies with the seasons. The larvæ, too, grow faster or more slowly, or pupate earlier or later from similar causes. And so no very definite date or period can be assigned to any one stage of any insect.

      Now let us return to one of the chrysalides that we have already watched through the earlier stages of its existence, and follow it in its future development.

      It is now, as we say, in its quiescent or dormant condition, but we must not suppose that it is always in a profound sleep, nor can we say that it is insensible to its surroundings. Touch it gently or surprise it with a puff of air from your mouth, and it will begin to wag its pointed tail, sometimes with such vigour as to send the body rolling round and round in its box. Lay it on a bed of cocoa-nut fibre or finely sifted soil and let it remain quite undisturbed for a few hours or days, and you will probably find that, by occasional movements of its body, it has made a slight depression in its bed, and lies partly submerged. I have known some chrysalides to completely bury themselves in this way during the course of a day or two, and others to partly expose themselves after having been lightly covered. Others again, I have observed, will move smartly if a strong light is suddenly turned on them. Many, too, certainly appear to have a strong objection to exposure to the direct rays of a hot sun; for, when thus exposed,