Now, the upper and lower portions of these rings are comparatively inelastic, and cannot themselves expand, though they can be opened wider at the sides in proportion to the interior expansion of the body. Meanwhile, the larva continues busily its sole business, that of eating, and increases rapidly in size, so that, within a certain time, its skin is stretched to the utmost, and can expand no more. Still the larva continues to increase, though its tight integuments cause it so much uneasiness that it ceases to eat, and at last the overstretched skin bursts, and the larva emerges, clad with a new skin, which has been forming under the old one. As soon as it is free, it takes a number of deep respirations, and in half an hour, or thereabouts, is so much larger than its cast skin, that to put it back again would be fatal. This process is repeated until the larva is about to assume the third or pupal state.

In consequence of this mode of development, the whole of the growth is completed during the larval state, and, however long an insect may live, it never grows after it has attained its perfect form ; and, though it is common enough to find insects though of the same species yet of very different sizes, the larger have not grown since their last change, nor will the small specimens ever attain the dimensions of their larger relatives. In a measure, the same rule prevails among mankind, and, though some may be giants and other dwarfs, the dwarf will never become a giant, nor has the giant ever been a dwarf, and, different as are their sizes, both ceased to grow when they attained the age of manhood.

The modes of passing through the successive changes of form are exceedingly variable in the different orders of insects, and are always most interesting to careful observers. I shall not inention them in this place, but shall give the descriptions of the metamorphoses together with the history of the different species.

Next -in order comes the statement that all true insects have six legs when they have attained the perfect form or Imago. The reader will see that this definition at once excludes all other Annulata. The Crustacea, for example, have a considerable number of legs, and the Arachnida are ei^htlegged, while the Myriapoda are, as their name infers, manyegged, and the Annelida have no legs at all. It is true

that ill some insects there only appear to be four legs, but, in these cases, the apparently missing organs may be discovered on careful examination, much reduced in size, but still present.

A similar observation may be made with regard to the antennae, or, as they are popularly called, ‘ horns,’ or ‘ feelers.’ The word antenna is a Latin one, signifying the yard-arm of a ship, and has been appropriately given to these organs. In most cases the antennae give great character to the aspect of an insect. In some of the Beetles, for example, they are slender, and each joint is so lengthened that the antennae are five times as long as the body. In others they are comparatively short, sometimes deeply toothed like combs, sometimes terminated with a round club, sometimes with the ends developed into a beautiful fan-like apparatus, and sometimes looking like a number of coins joined together by a string running through their centre. The knob-tipped antennae of the butterflies are an unfailing characteristic whereby these insects can be distinguished from the moths, with their sharp-tipped antennae.; while in the latter group of insects, the antennae of the male are often wide and feathered, those of the female being mere jointed threads, without any feathering whatever. Many insects seem to be altogether without antennae, but, like the undeveloped legs already mentioned, they can be found in their places, though so small as to escape a hasty observation.

Having now briefly examined the general characteristics of insects, we will take them in detail.

Among the insects, the Coleopteea, or Beetles, are acknowledged to hold the first rank, their development being more perfect than is found in any of the other orders. The name of Coleoptera is composed of two Greek words, signifying sheathwings, and is given to this order of insects in consequence of their leading peculiarity, which is, that the upper pair of wings is modified into horny or leathery cases, called elytra, useless in flight, but employed in protecting the membranous under pair of wings, which alone are used in flight. In many Beetles the lower pair of wings is not developed, and in a few both pairs are practically wanting, though the practised eye can always detect them in a rudimentary form. The wings and

elytra, together with other portions of the Beetle, will presently be figured and described.

The changes, or metamorphoses, of the Beetles, though singularly interesting, are not easily seen, as Beetle larvae require food which is, as a rule, not easily procured, and in many cases is so noisome that few persons would like to meddle with it. A great number are carnivorous, feeding upon various living creatures, so that to supply them properly with food is next to impossible ; while, as the majority of them pass two years or more in the larval state, the process of rearing them is tedious as well as difficult.

All who have had silkworms, or have been in the habit of watching insects when at liberty, are familiar witli the appearance of the three principal forms assumed by the moths and butterflies in their' different stages of growth — the caterpillar, with its soft, cylindrical, ringed body, the pupa or chrysalis, covered with a hard, shelly case, and the perfect insect, with its beautiful wings. Now, although the Beetles pass through similar changes, they do not assume similar forms. The larva of the Beetle is, like that of the moth or butterfly caterpillar, soft and ringed, and sometimes so resembles the caterpillar that it may easily be mistaken by anyone unskilled in entomology. Figures of the larvae will be given in connection with the different species.

Thus far the Beetle and moth bear some resemblance to each other, but when they come to assume the pupal form, they are so dissimilar that no one could possibly mistake one for the other. In the moth pupa all the limbs are hidden under a hard covering, but in the Beetle pupa all the members of the insect are visible, though they are covered with a skin which binds them down, and prevents them from being used until the insect attains its perfect form, and bursts through the investing skin. A figure of the larva and pupa of a Beetle may be seen by referring to the Bacon Beetle {Dermestes lar~ danus), Woodcut XI.

If the reader will carefully examine the various stages of insect life, he will see that, whether the creature be in the larval, pupal, or perfect state, the number of rings of which it is composed are the same. Take, for example, a Beetle larva, and it will be found to consist of thirteen rings, or

segments. The first of these forms the head, the next three

carry the legs, and the remaining rings constitute the body.

Should the same larva be successfully reared, and examined after it has reached the perfect state, it will be found to have precisely the same number of rings, though some are fused

together, and others are greatly modified.

There are few things more marvellous than the development of a Beetle — say, for example, the Stag Beetle, because we shall presently examine one of these insects in detail. In its larval state it is a large, fat, soft grub, with legs so disproportioned to the size of its body that it cannot walk, but can only move about while lying on one side. It lives in the dark, buried in the interior of some tree, and feeds upon the fragments of wood which it bites off with its short but sharp and powerful jaws. In its perfect state, it is furnished with highly developed legs, with two wide and powerful wings, sheltered under their horny elytra, with an elaborately organised mouth, and two enormous jaws, while the antennae and eyes are in themselves absolute wonders of mechanism. The larva of this Beetle is almost exactly like that of the cockchafer, shown in Plate V. ; and the reader will see that it is hardly possible to imagine a more complete contrast than exists between the very shapeless grub and the insect in its perfect form.

In the accompanying illustration we have an example of the Beetle, taken to pieces so as to show the various parts. The Stag Beetle has been chosen for the purpose.

We begin with the head and its appendages. Fig. 1 shows the mandibles, or upper jaws, which in the male Stag Beetle are of very great size. Fig. 4 shows the maxillae, or lower jaws, with the maxillary palpi, or jaw-feelers. Fig. 4a. Fig. 3 shows the labium, or lower lip, with the labial palpi, or hpfeelers, 3a. Next come the antennae, or feelers. Fig. 2. These organs are divided into two parts — namely, the scape, or long joint nearest the head. Fig. 2a, and the club, 2h. This latter portion is subject to most extraordinary variations of form, as will be seen in the following pages.

The head itself is shown at Fig. 5, the upper surface being liere given. 5aa are the eyes, bh the vertex, or cro\ra of the head. 5c is the occiput, or back of the head ; and 5d the

Lucanus cervus. Dissection.

Parts of the Head.—1. Mandibles, or jaws. 2. Antennae. 2a. Scape. 2b. Club. 3. Labium, or lower lip. 3a. Labial palpi, or lip-feelers. 4. Maxillae, or lower jaws. 4a. Maxillary palpi, or jaw-feelers. 5. Head, upper surface. 5a. Eyes. 5b. Vertex, or crown. 5c. Occiput, or back of head. 5d. Clypeus, or shield. 6. Head, under surface. 6a. Eyes. 6b. Insertion of antennae.

Parts of Thorax and Abdomen.—7. Pronotum, or upper surface of thorax. 7a. Lateral margin. 7b. Anterior margin. 7c. Posterior angles. 7d. Posterior margin. 7e. Anterior angles. 8. Prosternum, or under surface of thorax. 8a. Sternum. 8b. Insertion of coxae. 9. Mesothorax and upper surface of abdomen. 9a. Mesothorax alone. 9b. Abdomen, upper surface alone. 10. Metasternum and abdomen. 10a. Metasternum alone. 10b. Abdomen, under surface alone. 10c. Parapleura, or side-pieces. 10d. Episterna, or breast-pieces. 12. Scutellum.

Legs.—11. Anterior, or first pair of legs. 11a. Tarsi, or feet. 11b. Tibia, or shank. 11c. Femur, or thigh. 11d. Trochanter. 11e. Coxa. 13. Intermediate pair of legs. 15. Posterior pair of legs.

The Wings.—14. Elytra. 14a. Suture. 14b. Lateral margin. 14c. Apex. 14d. Base. 14e. Disc. 16. Wings folded on abdomen. 17. Left wing expanded. 18. Right wing folded.

clypeus, or shield, which covers the actual mouth. Fig. 6

shows the under side of the head. 6aa are

insertion of the the eyes, 66 the antennae.

As reference has been made to the eyes, it must be mentioned that these organs, although apparently only two in number, are in reality compound eyes, being made of a vast number of facets gathered into two groups, one on each side of the head. There is an apparent exception to this definition in the well-known Whirligig Beetles (Gyri/ni), which appear to have four- eye-groups, two above and two below. This exception IS, however, more apparent than real ; the eye-groups being in fact only two, but each pair being crossed by a band of the homy material of which the outer skeleton is composed. The compound eyes can be seen to great perfection in some of the butterflies ; but for this purpose, a careful manipulation of the microscope is needed.

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