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 When disturbed it is very sluggish, the head being immediately withdrawn into the large thoracic segment and completely concealed.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 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).
One of our commonest beetles, found in great abundance in all moist wood when much decayed, the favourite trees being apparently rimu and matai. Its cylindrical larva may be taken in similar situations, and much resembles in general appearance the well-known "wire-worm" of England, whose destructive habits, however, it does not share. At present, whilst bush-clearing is going on, its influence is beneficial, as it devours large quantities of useless wood, which is thus rapidly broken up and got rid of. The pupa is enclosed in an oval cell, constructed by the larva before changing, from which the perfect insect emerges in due course. When first exuded its colour is pale red, but this rapidly changes into dark brown after the insect has been hardened by exposure to the air. Specimens are often met with of every intermediate shade, and are rather liable to deceive the beginner, who mistakes them for distinct species. An account of a small Dipterous insect infesting this beetle in its preparatory states will be found on page [62].
Group Longicornia.
Family Prionidæ.
Prionus reticularis (Plate [II]., fig. 3, 3b larva, 3a pupa).