The sexes of this species are readily distinguishable, the male (Plate [XVIII]., fig. 2) possessing an immense head furnished with a pair of enormously powerful mandibles. The female (Plate [XVII]., fig. 8) is a more attractive insect, her gracefully curved ovipositor and smaller head having a much more pleasing appearance than the terribly menacing jaws of her mate. Both sexes are able to give severe bites, but it is extremely doubtful whether they would prove anything worse than slight mechanical injuries, as the insect is not likely to be poisonous. I am, however, unable to speak from experience.
Family Gryllidæ.
Xiphidium maoricum (Plate [XVII]., fig. 1).
This pretty insect may be found in great abundance round Nelson during the autumn, but is rarer in the Wellington Province. Its presence may be at once detected by the curious chirping heard in various directions shortly before sunset and lasting till eight or nine o'clock in the evening. This sound is produced with the wing-cases, which the male insects may be seen vigorously rubbing together. The females are quite mute, and they may be also distinguished by possessing a short curved ovipositor at the end of the body. The peculiarly leaf-like shape of the insect and its bright green colour render its discovery amongst the herbage a most difficult matter, even when its whereabouts is indicated by its cry—in fact, were it not for their music, there is little doubt that very few of these insects would ever be captured, as they are practically invisible, and are an instance of protective resemblance carried to great perfection.
When disturbed these crickets fly about twenty yards and again settle in a bush or amongst herbage, carefully avoiding alighting on the ground where they would be readily visible. Their flight is somewhat feeble for such large insects. Great care must be taken, when capturing specimens for preservation, not to hold them by their powerful hind-legs, as they will not infrequently cast one off while endeavouring to escape.
I have not yet noticed the larva of this species, but should imagine it would closely resemble a wingless imago.
Family Locustidæ.
Caloptenus marginalis (Plate [XVII]., fig. 4).
This is the little grasshopper which rises before our footsteps in swarms on a hot summer's day; it is one of the last insects to leave us in the autumn, being frequently found in warm situations on fine days in the middle of winter. Owing to its great abundance this species must inflict considerable damage on the grass, as it has taken up its quarters like the English grasshopper in the cultivated fields, where an unlimited supply of food is always at hand. Formerly, no doubt, it was much less common round Wellington than at present, owing to the few open spots then existing, none of these grasshoppers being found in the forest.
The perfect insect may be recognized by the rudimentary wings which are present on the thorax, thus causing it to closely resemble the larval form of many of the winged species, and for which it might readily be mistaken were its true character unknown.