Part 10

Family TIPULIDÆ.

Cloniophora subfasciata (Plate V., fig. 3, 3a larva).

Tolerably common in damp gullies during summer and autumn. The larva (Fig. 3a) inhabits decayed henau logs, {51}drilling deep into the wood, where its burrows are seldom noticed, as they are filled up with refuse almost as soon as they are made. The pupa resembles that of Tipula holochlora, but is rather more attenuated in the body, and the thoracic horns are slightly thicker. It is not enclosed in any cocoon, but lies amongst the powdery wood, wriggling to the surface when about to emerge. The illustration represents the male insect, the female having a much stouter body, with short thick legs; she also differs in her antennæ, which are much less branched than those of the male.

Family TIPULIDÆ.

Rhyphus neozealandicus (Plate V., fig. 4, 4a larva, 4b pupa).

A most abundant species occurring in most damp situations throughout the year. Its larva (Fig. 4a) closely resembles a small worm, being of an elongate form attenuated at each end. The skin is very hard and of a dull yellow colour, with black markings. The food of this insect consists of decaying vegetable matter, which it procures by means of two small appendages, situated on each side of the mouth, and which it is continually moving about in search of suitable materials. The pupa is a curious object (Fig. 4b), the two little respiratory horns having a singular resemblance to a pair of ears. It is enclosed in a small oval cell about one inch below the surface of the earth, the insect working its way to the air before emergence. The perfect Rhyphus may be almost regarded as one of our domestic insects, and is seldom found in the open country, but frequents cowhouses and other farm buildings in great numbers, the larvæ feeding on the manure in these situations. It is often mistaken by ignorant people for the mosquito and at once destroyed, but quite unfairly, as the species is in reality perfectly harmless, frequently {52}benefiting mankind by the removal of considerable quantities of effete matter, which if allowed to remain could not fail to be injurious.

Family TIPULIDÆ.

Bibio nigrostigma (Plate V., fig. 5, 5a larva, 5b pupa).

This insect is very abundant during the spring months, but rapidly disappears, and few specimens are noticed after Christmas. Its larva (Fig. 5a) inhabits the woody powder often found under logs, which frequently consists of the accumulated excrement of wood-boring insects. It is gregarious in its habits, being found in large companies of fifty or a hundred individuals. When first disturbed these appear as a wriggling mass, but very shortly become so still that they can only be distinguished with the greatest difficulty from morsels of bark. A considerable portion of the powdered wood is also retained on the body of the insect by a row of short spines situated in the middle of each segment, which helps to render the larva still more inconspicuous. In this condition it remains for at least eight months, during which time growth takes place very slowly. About September the larvæ separate, each being afterwards transformed into a small yellowish pupa (5b), whose abdominal extremity is usually retained within the old skin, thus closely resembling that of the genus Ceratopogon. I have figured this pupa entirely naked, in order to show its characteristics, some of which are rather remarkable, more completely, the agglutination of nearly all the anterior portions of the body being especially noteworthy. The perfect insects may be found everywhere, the males sucking honey from the flowers and performing many antics in the air, often clinging hold of one another and whirling about together. The female seldom flies, but is usually observed crawling about fences or the trunks of trees. She may be at once recognized by her heavy body {53}which is very large when distended with eggs. Her general colour is dull red, thus differing widely from the male insect represented in the illustration (Fig. 5).

Family TIPULIDÆ.

Simulia australiensis (Plate VI., fig. 1, 1a larva, 1b pupa).

Every one knows the sandfly, the little black insect that so persistently perches on our hands and faces and inflicts its painful punctures, which in many cases are followed by large swellings, often lasting for several days and causing much irritation. Its larva (Fig. 1a) inhabits clear running water, climbing about in strong currents by means of a pair of suckers situated at each end of the body, two being placed on the prothoracic segment just behind the head and two others close to the anal extremity. These the insect employs rather curiously, the anterior pair being first affixed and the others drawn up close behind them, its elongate body consequently forming a loop. Clinging by the posterior suckers for a moment the larva then reaches forward, re-affixes the anterior ones, and draws up the posterior as before. Breathing is performed by two spiracles situated on the last abdominal segments near the hind pair of suckers. Two large air-tubes originate from these and run forwards, giving off branches to all parts of the body; they terminate in a number of air-sacs in the thorax. The food of this larva consists of animalculæ, which are no doubt obtained by drawing the two ciliated appendages rapidly through the water several times in succession, their contents being afterwards gathered up by the smaller organs and passed into the mouth. When about to assume the pupa state the insect covers itself with a glutinous envelope, which is firmly joined to the under side of a leaf, the transformation taking place within a few days. The pupa can hardly be distinguished from a small moth chrysalis except for a pair of branching {54}filaments, which arise from the top of the thorax and serve the purpose of gills (Fig. 1b). Before emergence the anterior segments are projected nearly out of the cocoon from which the perfect sandfly makes its escape, and floating to the surface of the water ascends the stem of an aquatic plant to expand its wings. I should here remark that as with the mosquitoes, the bloodthirsty propensities of the present species have no doubt been acquired since the arrival of man and other warm-blooded animals.

Group BRACHOCERA.

Family TABANIDÆ.

Tabanus impar (Plate VI., fig. 6).

I have figured this fine species as a representative of a most important family of Dipterous insects, but am at present quite unacquainted with its life-history. It occurs plentifully on the margins of the forest throughout the summer.

Family BOMBYLIDÆ.

Comptosia bicolor (Plate VI., fig. 2).

This conspicuous species is very abundant in glades throughout the summer, flying with great rapidity, and delighting to suck honey from the numerous shrubs which are in blossom at that time of year. It is a social species, and is usually found in companies of fifteen or twenty individuals, which engage in endless dances, two insects often seizing one another on the wing and then revolving together like a wheel in rapid motion. Their manoeuvres in avoiding the strong gusty wind, so often prevalent in early summer, are also interesting; the insects play upon the wing whilst the air is quiet, but if a breeze springs up they instantly settle on the nearest bush, rising to renew their sports when it is again calm. These flies are rather variable in colour, some specimens being dark brown, {55}whilst others are more or less covered with greyish-white hairs; individuals are also often met with quite black and shining, their hirsute covering having been completely rubbed off. The female may be at once recognized by her solid, fleshy abdomen, that of the male being inflated by two great air-bladders, which cause that portion of the body to appear semi-transparent when the insect is held up to the light. The figure (2) is taken from a specimen of the latter sex.

Closely allied to the present insect is Comptosia virida, n.s. (Fig. 3), which can be at once distinguished by its brilliant green eyes and pale grey clothing. The larva of this species is a large white maggot, rather robust, and possessing a small head. It inhabits the dense moss growing on the trunks of trees in the forest, feeding on the roots of these plants, and finally forming an oval cocoon, in which it changes into the pupa shown at Fig. 3b. The perfect insect appears in a few weeks' time, when it may be taken in similar situations to C. bicolor, but in much fewer numbers.

Family ASILIDÆ.

Sarapogon viduus (Plate VI., fig. 4, 4a larva, 4b pupa).

A voracious insect, frequenting all dry sand-banks and pathways throughout the summer, and destroying the numerous minute diptera found in those situations. These unfortunate victims are drilled through the thorax by their destroyer, which sucks them completely dry with its long beak-like proboscis. The larva (Fig. 4a) inhabits rotten wood, chiefly feeding upon the moist, powdery portions. It is usually somewhat sluggish, but when disturbed hops about with electrical rapidity. The head is very minute, and the elongate body consists of twenty segments, a number very unusual among larvæ, the normal number being twelve exclusive of the head. It lives for a {56}considerable time and is finally transformed into the blunt-looking pupa, drawn at Fig. 4b, without having previously constructed any cocoon. From this the perfect insect emerges in a month or six weeks' time, commencing its work of destruction as soon as its wings are hardened, which takes place within a few hours.

Family STRATIOMIDÆ.

Exaireta spiniger (Plate VI., fig. 5).

Abundant during November, when it may be taken in great numbers in the vicinity of water. The larva is probably aquatic, but I have not yet observed it, although its habits would, no doubt, be very interesting. The perfect insects frequent flowers, and are generally very sluggish in their movements.

Family ACROCERIDÆ.

Acrocera longirostris, n.s. (Plate VII., fig. 4).