Part 6

Dryocora Howittii (Plate I., fig. 6, 6a larva).

This quaint-looking little insect occurs occasionally in damp matai logs, when in an advanced state of decay. The larva (Fig. 6a) is very flat and thin, possessing the usual thoracic legs, which, however, are rather short. The last segment of the abdomen is furnished with an anal proleg and a pair of small setiform appendages. Its mode of progression is very peculiar, resembling that of the Geometer larvæ among the Lepidoptera.

The thoracic legs are first brought to the ground, and the rest of the body is then drawn up in an arched position close behind them. The anal proleg then supports the insect while the anterior segments are thrust out, and the others follow as before. This method is only employed on smooth surfaces, the larva crawling along elsewhere in the usual manner.

The perfect beetle is a very sluggish insect, and difficult to find owing to its colour, which closely resembles that of the wood in which it lives.

Family ENGIDÆ.

Chætosoma scaritides (Plate I., fig. 2).

This insect may be at once recognized by its peculiar shape, no other New Zealand beetle resembling it in this respect. Although tolerably common and generally distributed, it is very seldom seen abroad, spending almost the whole of its life concealed in the burrows of various wood-boring weevils. Its larva, which feeds on the grubs {25}of these insects, is of a pinkish colour, very fat and sluggish; the head and three anterior segments are strong and horny, the legs being rather short. It undergoes its transformation into the pupa within the weevil burrows, when the limbs of the perfect insect can be seen folded down the breast, the wings and elytra being much smaller than in the beetle. Specimens in all stages of existence may be readily procured by splitting up old perforated logs which have been long tenanted by weevils.

Group BRACHELYTRA.

Family STAPHYLINIDÆ.

Staphylinus oculatus (Plate I., fig. 5).

This is the New Zealand representative of S. olens or the "Devil's Coach Horse," one of the most familiar of British beetles. It is found occasionally in the neighbourhood of slaughter-houses, and may be at once distinguished from any of the allied species by a large spot of brilliant scarlet situated on each side of its head behind the eyes; this very conspicuous feature has given it the specific name of oculatus. I am at present unacquainted with the transformations of this fine insect, but they will probably closely resemble those of the typical species (S. olens) described in the majority of standard books on European Coleoptera. This beetle may be frequently seen flying in the sunshine, when it has a most striking appearance, owing to its large size and rapid motion. An unpleasant odour is found to arise when it is handled, this being noticeable in nearly all the members of the family. These beetles are comparatively numerous in New Zealand, the genus Philonthus comprising several elongate active insects, of which P. oeneus is one of the commonest, and may be found abundantly amongst garden refuse. Others frequent the seashore, feeding on decaying seaweed, and {26}may be noticed flying in all directions along the coast immediately after sundown. Another genus (Xantholinus) includes a number of interesting beetles found in old weevil burrows, and probably feeding on their inmates.

Group LAMELLICORNES.

Family LUCANIDÆ.

Dorcus punctulatus (Plate I., fig. 7).

An abundant species chiefly attached to the red pine tree or rimu, where it may be found concealed beneath the scaly bark, in the angles of the trunk near the roots. When disturbed, it folds up its legs and antennæ on its breast, and, extending its powerful jaws, awaits the approach of the enemy, ready to bite anything coming within its reach. These, however, are purely defensive measures, the insect being quite harmless when left alone. The larva is at present unknown to me. Another species, D. reticulatus, is a much handsomer insect than the preceding; it may be at once recognized by four deep impressions in the thorax, filled in with light-brown scales; the margins of the elytra are similarly scaled, as well as four spots on each elytron, the remainder of the beetle being dark-brown and shining. It is generally found in totara bark, but is much scarcer than the last species. One small specimen I possess, remarkable for its brilliant appearance, was taken under the bark of a stunted black birch tree, over two thousand feet above the sea-level.

Family MELOLONTHIDÆ.

Stethaspis suturalis (Plate I., fig. 8, 8a larva).

This conspicuous insect occurs abundantly in all open situations. Its larva (Fig. 8a) inhabits the earth, feeding on the roots of various plants, and is especially abundant {27}in paddocks, where it occasionally does considerable damage to the grass, and threatens ere long to become as great a pest as its first cousin, the renowned Cockchaffer of England (Melolontha vulgaris), whose fearful ravages need no description. It may be taken as a typical larva of the family, the rest differing from one another in little else than size. When full-grown it is quite as large as the illustration, and is nearly always in the position there indicated, owing to the size of its posterior segments and the absence of any anal proleg, which compel it to lie always on its side. I have not yet succeeded in obtaining the pupa of this insect, although larvæ may be frequently found enclosed in oval cells, evidently about to undergo their transformation. Several of these have been kept in captivity, but they have hitherto always died without undergoing any change. I have, however, no doubt as to its being the larva of S. suturalis, as there are no other large Lamellicorns found near Wellington to which it could possibly be referred. The perfect beetle appears in great numbers from November to March; it is best taken at dusk, when it flies with a loud humming noise, about four feet above the ground. If knocked down it always falls amongst the herbage, and is not readily perceived until a few minutes later, when the humming noise is resumed as the insect again gets under weigh, and the would-be captor must not lose time if he wishes to secure it. Occasionally individuals are seen disporting themselves on the wing during the day, but this must be regarded as a purely exceptional circumstance. Unlike the majority of nocturnal Coleoptera, this insect does not appear to be attracted by light; in fact I have never obtained any specimens by this method, although most other night-flying beetles may be taken in goodly numbers at the attracting lamp.

{28}Family MELOLONTHIDÆ.

Pyronota festiva.

This brilliant little insect is extremely abundant amongst manuka, during the early summer. In general appearance it reminds one of a miniature specimen of the last species, but is more elongate in form; the green thorax and elytra are also much brighter. The latter are bordered with flashing crimson, the legs and under surface being reddish-brown, sparsely clothed with white hairs. A small Lamellicorn grub, found amongst refuse in manuka thickets, is probably the larva of this insect; it is less thickened posteriorly than that of S. suturalis, but otherwise closely resembles it. The perfect insect is diurnal in its habits, flying round flowering manuka in countless numbers on a hot day. The descent of thirty or forty of these little beetles on to the beating sheet, out of a single bush, is of frequent occurrence, and is particularly noticed by the New Zealand entomologist accustomed to the meagre supply of specimens offered in the majority of instances.

Group STERNOXI.

Family ELATERIDÆ.

Thoramus wakefieldi (Plate II., fig. 1, 1b larva, 1a pupa).

This fine beetle may be taken under rimu bark in tolerable abundance, and is often observed flying about at dusk during the summer. Its larva inhabits rotten wood, usually selecting the red pine, in which it excavates numerous flat galleries near the surface of the logs. When disturbed it is very sluggish, the head being immediately withdrawn into the large thoracic segment and completely concealed. The legs are very minute, and are of but little use in walking, the insect being chiefly dependent for locomotion on its large anal proleg, which is furnished with numerous horny spines. When full-grown this larva closes up one end of {29}its burrow, and thus forms a closed cell, in which it is transformed into the pupa shown at Fig. 1a, remaining in this condition until the warmer weather calls the insect from its retreat. Two closely allied species are T. perblandus and Metablax acutipennis. The former is occasionally found under the large scales on matai trees, and resembles the present insect in general appearance, but is much smaller and more elongate in form, its elytra being also ornamented with longitudinal rows of yellowish-brown hairs. The latter may be often taken on the wing in the hottest sunshine, and is chiefly remarkable for its elongate prothorax and pointed elytra; its colour is dark reddish-brown, ornamented with a few scattered white hairs. All these insects possess the singular habit of leaping into the air when placed on their backs, the last-named species exercising this faculty in a most marked degree. The movement is effected by the joint between the pro- and meso-thorax, the sternum of the former being elongated into a long process, fitting into a corresponding cavity in the latter, so that by means of the two being suddenly brought together, the insect is thrown high into the air with a loud clicking sound, hence the English name of the Skipjack or Click Beetles, the scientific name, Elater, doubtless having reference to the same habit. The object of this curious arrangement is in all probability twofold; the sharp click and rapid movement of the insect deterring many enemies from attacking it, whilst the short legs of the beetle, which are quite unable to reach the ground when it is thrown on its back, render a special contrivance necessary.

Group HETEROMERA.

Family TENEBRIONIDÆ.

Uloma tenebrionides (Plate II., fig. 2, 2a larva, 2b pupa).