Family Cicindelidæ.
Cicindela tuberculata (Plate [I]., fig. 1, 1a larva).
This is a very abundant insect found throughout the country in all dry situations. It delights in hot sunshine, and may be constantly observed flying from our footsteps with great rapidity as we walk along the roads on a hot summer's day.
Its larva (Fig. 1a) is an elongate fleshy grub, the head and first segment being horny and much flattened, and the body provided with two large dorsal humps, each bearing at its apex a slender curved hook.
The burrows of these insects are very conspicuous, and must have been noticed by every one, in garden paths, sandbanks, and other dry situations; they are sometimes very numerous, and may be best described as perfectly round shafts, about one line in diameter, and extending to the depth of three or four inches, generally slightly curved at the bottom. The sides are perfectly smooth, and the larva may be often discovered near the mouth of its burrow, using its dorsal hooks to support it, and thus having both legs and jaws free to dispose of the unfortunate insects that fall into its snare. These usually consist of flies and small beetles, which appear to be urged by curiosity to crawl down these pitfalls, and thus bring about their own destruction. By reference to the figure it will be seen how admirably the hollowed head and prothorax serve the purpose of a shovel to the larva, when forming its shaft. These burrows are first observed about the middle of November; the perfect insects coming abroad three weeks or a month later, when they may be often seen in the neighbourhood of their old domiciles. They are very voracious, devouring large quantities of flies, caterpillars, and other insects, some of which are much superior to themselves in size. On one occasion I saw a male specimen of Cicindela parryi (a species closely allied to but smaller than C. tuberculata) attack a large Tortrix caterpillar, an inch and a half in length. The beetle invariably sprang upon the back of the caterpillar and bit it in the neck, being meanwhile flung over and over by the larva's vigorous efforts to free itself from so unpleasant an assailant. During the fight, which lasted fully twenty minutes, the beetle was compelled to retire periodically to gain fresh strength to renew its attacks, which were eventually successful, the unfortunate tortrix becoming finally completely exhausted. The beetle devoured but a very small portion of the caterpillar, and abandoning the remainder went off in search of fresh prey. Eight other closely allied species of Cicindela are described by Captain Broun in the "Manual of the New Zealand Coleoptera," but they offer no especial peculiarities, and C. tuberculata may be taken as a type of the genus.
Family Carabidæ.
Pterostichus opulentus (Plate [I]., fig. 3, 3a larva).
This fine beetle is very common in most wooded situations in the Nelson district; it may be at once distinguished from the numerous other closely allied species by the beautiful metallic coppery tints that adorn its thorax and elytra.
During the day it is usually discovered concealed under logs and stones, and when disturbed, rushes into the first crevice to get out of the light. At night time, it comes abroad to feed, killing an immense number of flies, caterpillars, and other insects, to satisfy its voracious appetite. Although of a most ferocious disposition, it is not wanting in maternal affection. The female, when about to deposit her eggs, excavates a small cavity nearly three inches square, in which they are placed. These she broods over until hatched, and probably some little time afterwards, as I have found a specimen close to a nest, which contained both eggs and larvæ, and the zealous mother furiously bit at anything presented to her. The eggs are oval in shape, quite smooth, and yellowish white in colour. The young larva is drawn at Plate [I]., fig. 3a; it is remarkable for its superficial resemblance to a small Iulus, and being found in similar situations to that animal, its mimicry has probably some useful object. The older larva differs chiefly in having the head and thoracic segments proportionately smaller. Twenty-one closely allied insects belonging to two genera are described by Captain Broun in his Manual, the largest being Pterostichus australasiæ, which is found in similar localities to the present species, but is not so common.
Group Hydradephaga.