which were necessitated in consequence. Therefore, the history of the wonderful adaptation of means to an end, as exemplified by all organic forms, can only be properly and philosophically understood when related to the past inorganic changes and evolutions of the earth's history.

CHAPTER V.

THE BUTTERFLIES AND MOTHS OF THE GREEN LANES.

HERE are few objects more generally noticed than the butterflies and moths which

give such animation to a country stroll. Of various colours and patterns, they

seem fit associates for the flowers and blossoms on which they love to dwell for a few seconds. The most careless observer has been amused by their fantastic flutterings, and many a boy has been educated into a naturalist through following them with his cap. The well-known metamorphoses through which they pass, also, are better known than the vital economy of any other forms of creature life. For a long time they were believed peculiar to the butterflies and moths, but naturalists now know that such a change is not peculiar to them-nay, that it is repeated and varied in many ways among the invertebrate animals. Let the three stages of caterpillar, chrysalis, and imago be undergone by three distinct creatures, instead of in the lifetime of

one, and we should have a strong analogy in the hydrozoa and jelly-fish. Structural investigation has shown that the immature organs of wings, &c, may be traced in the caterpillar of a butterfly when it is only a few days old, and before it has attained anything like the bulk of body which its voracious appetite presently obtains for it. Let any one who wishes to trace the gradual perfection of the organs from this immature stage to their perfection, carefully study Professor Duncan's lecture, on Insect Metamorphoses,' delivered before the British Association in 1872.

If you care to sacrifice one of the commonest butterflies you may meet with in a country walk to your new-found love for science, you will not be without food for wonder for many a day to come, especially if you possess two things—a microscope and patience! In its eyes you may perceive compound lenses, thousands in number, each one of which is capable of refracting a ray of light proceeding from any object. In its coiled-up proboscis you discover an ingeniously-jointed and flexible tube; and in the antennæ marvellous and mysterious organs of a sense with which we mortals are unacquainted. For it is a well-known fact among entomologists, that if the young virgin female of many species of moths and butterflies be enclosed in a perforated box, it will draw numbers of the males from all parts of the horizon to it. The sense that can be operated upon so refinedly must transcend

anything with which we are acquainted. For, immediately one such male insect has paired with the female, the charm is broken-no longer are the ardent cavaliers attracted!

The internal structure of the Lepidoptera―a name well given to butterflies and moths, as we shall presently see is also of great interest to the microscopist. The mouth-tube is not formed for breathing, but for suction only. Aëration is carried on by a series of tubes ramifying through the body, and receiving the air through openings in the sides of the abdomen, which resemble, to compare small things with great, the port-holes of a ship. These are called the trachea, and when you dissect and examine such portion of an air-tube through the microscope, you see it is formed of a spiral thread of chitine so closely wound on itself as to be impervious. The nervous system runs through the body from head to tail, and is gathered into knots, from which radiate threads of nerves, where the legs and wings are situated. Just as we find our towns and cities best supplied with lines of converging rails and telegraph wires, to administer to the more active commercial and social life, so do we always find in the invertebrate animals the nervous ganglia gathering thickest in those parts whence motion or other active functions have to proceed.

To the young student of microscopy, we can recommend no objects which are so readily obtainable, or that can be better studied by him, than the

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scales of a butterfly's or moth's wing. He may never have heard of such scales, but when we tell him we simply mean the coloured dust that powders his fingers after handling a butterfly, and that this

dust when placed under the microscope assumes a distinct form or shape, which varies according to the species of butterfly from whose wings it has been taken-he may feel inclined to experiment. Indeed, as regards their wings, butterflies and moths differ from dragon-flies, beetles, &c., chiefly in having these