The only winged Blattidæ found round Wellington are Blatta conjuncta, and Periplaneta orientalis. The former (Fig. 6), may be occasionally noticed under the scaly bark of rimu and matai trees, but a sharp eye and hand are needed to effect a capture, the insect running with marvellous rapidity. The latter species I have not yet noticed, but as it is the ordinary "cockroach" of Europe its habits have already been amply described.
Family Mantidæ.
Tenodera intermedia (Plate [XVII]., fig. 2).
A local species confined, I believe, to the South Island, and occurring in some numbers round Nelson, where my specimens were obtained. It seldom flies, but crawls stealthily about the trunks of trees, in the hottest sunshine, capturing and destroying great quantities of insects, its green colouring and leaf-like form rendering it very inconspicuous to its victims. The purple spots on the tibiæ of this insect are very noticeable, and resemble small drums in structure, hence they are regarded by Mr. A. H. Swinton ("Insect Variety," page 239), as the organs of hearing. These curious drums may be also found in insects belonging to nearly all the remaining families of the Orthoptera, but, as we find no auditory organs occupying a similar situation in any other groups of insects, I think that Mr. Swinton's explanation of their function must be regarded at present as a somewhat doubtful one.[[21]]
Family Phasmidæ.
Acanthoderus horridus (Plate [XIX].).
The curious Stick Insects are familiar to most people from their remarkable similarity to the twigs of trees.
The present species is one of the largest, the mature insect frequently attaining a length of five inches. It is best taken at night, when it may be readily discovered, feeding on the leaves of shrubs, and suddenly becoming perfectly motionless when the lantern is turned upon it. The favourite plant for this (and indeed most of the species) is the white rata, upon which they are often seen in large numbers when the entomologist is collecting Lepidoptera in autumn. One of the commonest species found in this way is Bacillus (hookeri?) chiefly remarkable for its great sexual disparities, the male resembling a very slender stick about twenty-eight lines long, while the female is nearly half as long again (thirty-eight lines), and much more stoutly built. A more systematic investigation of this family is needed before we can pretend to correctly determine the various species, as there is little doubt that in other cases the sexes will be found quite as divergent. In addition to this the insects are most variable in colour, and their completely apterous character rendering the distinction between larva and imago a matter of considerable difficulty, it is very probable that some of the smaller species may be only immature specimens of the larger ones.
Stick insects are easily kept in captivity, and will not be found devoid of interest. They are great eaters, and grow with considerable rapidity, frequently casting their skin, a task of no easy accomplishment, which I once had the pleasure of watching in the case of a specimen of Acanthoderus prasinus which I had under observation for several months.
The insect first suspends itself by its hind pair of legs, keeping the others in the same position as when walking, the head is bent in, and the antennæ are placed along the breast, the long abdomen hanging over backwards. The skin then splits along the back of the thorax, and the head and thorax are gradually pushed out. The front and middle legs are immediately afterwards extracted, the long femora and tibiæ easily passing the sharp angles in the exuvia, owing to their complete flexibility. When these are finally clear, the insect reaches forwards with its fore-legs and draws the abdomen and hind-legs out of the old skin, which remains attached to the branch until dislodged by some accident.