Insect Oddments

New Zealand Herald, Volume LXXV, Issue 23020, 23 April 1938, Page 10 (Supplement)

Insect Oddments

TWO large' stick insects were recently sent to me from the West Coast, South Island, near Lake Brunner. They were alike in being about six inches long and in their resemblance to woody twigs but were unlike in colour, one being greyish-brown and granular and the other bright green with a few thornlike px-ojections on its body. In spite of their superficial difference in appearance I think they both were of the same species, for there is considerable variation in colour and skin texture in the large females; males are smaller and more uniform in appearance. Deceiving the Birds The protective value of such shape and coloration is readily apparent and, as ono would expect, the resemblance of the bodies of these insects to plant tissue is only superficial. A more remarkable state of affairs is revealed I in the form and appearance of the stick insect's eggs. Until recently I bad not soon actual specimens of these extraordinary eggs, but both the Lake Brunner females obligingly laid a num-

her in the tins in which they were posted. The eggs are exactly like shrivelled hard brown seeds, and wherever under natural conditions they happen to be laid would escape the closest scrutiny of bird or other possible enemy. * Eggs Like Seeds The structure of these eggs represents the climax of a series of peculiarities associated with stick insects, lhey have not only a general similarity in size shape, colour, and external texture to a seed, but the anatomical characters of certain seeds are reproduced on the external surface. 1' urthermore, naturalists who have examined these eggs declare that tho minute structures of these curious capsu es cannot be distinguished microscopical.y from plant structures. lor a resemblance to bo protectivo it would need to be onlv skin deep and this seems to be a case of similarity carried beyond the point needed to make it effectn e. It would appear to bo not capable or explanation in the present state or our knowledge of tho life pattern of stick insects. Praying Mantis Another busy layer of eggs at this season is tho praying mantis, an insect of the same order as the stick insert but of very different habits. The female mantis, hatched in spring, does not become mature until March and it s usually in April that the eggs are laid. The compact egg containers may be found on many kinds of suitable rough surface —a twig a stone, a The mantis produces tho material in a frothy mass in which the layers of eggs aro placed until 100 or more o them are embedded in it The capsule hardens and remains sealed until the following spring when the joung emerge from it as the eggs hatch.

An Autumn Survey

By R. A. FALLA, MA

The grasshoppers, locusts and crickets that make up tho rest of the order orthoptcra are all active in late autumn. It has taken most of them six months to pass through the immature growth stages and successive moults that precede maturity and their adult existence is short. It is perhaps because of the'ir tropical ancestry and affinities that few of them survive the colder weather, but their habits in temperate climates ensure that the eggs are provided for throughout the winter. Ihe native tree crickets, or wetas, of New Zealand are among tho few exceptions to this rule and they may be found singly, in pairs, or in larger "groups hidden away at any time through tne winter. Destructive Earwig One or two questions relating to insects have been asked by various correspondents lately and this opportunity may be taken for a, note or two in answer. A Marlborough resident asks if 'it is true that the destructive earwig was originally brought to New Zealand intentionally for some scientific purpose and has become a pest, I here is no justification for the widespread belief that various insects intentionally introduced have become pests. It is n<?t known how tho European earwig

reached here, except that it was accidentally. It is unfortunately common in many parts of the South Island, less so in the North. It is destructive to vegetables, flowers, fruit, and material composed of sugar and starch. The larger and darker species common in the Auckland district is much less destructive. Earwig Legend Old wives' tales about earwigs and their habits are still current. In this case probably the name has suggested the myth. "Wig" seems to be a corruption of "wing," the wing in certain species being shaped like an ear. lhe insect has, however, gained the unmerited reputation of crawling into peoplo's ears and eating its way mto the brain! In spite of the absence of proof this legend is still widely believed in parts of and North America, perhaps even in New Zealand. "Devil's Coach Horse" A beetle very like an earwig has been sent to me in mistake for one. It is, however, a beetle known as Staphyloma oculatus or more vulgarly the "Devil's Coach Horse." The latter name is probably derived from the fact that it prances about with its "tad in the air when on the defensive. Seen at rest, this beetle appears to have absurdly small wings—at any rate the protective cases, or elytra, cover only the first few segments of the abdomen. When it flies, however, large gauzy wings suddenly come into action, it is worth while watching what happens when the insect comes to rest again. The transparent hind wings droop like a veil at first over the black body, but gradually they seem to be reduced in size and to disappear steadily beneath the small elytra. They have been drawn up and folded like an intricate fan.