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). An extraordinary and very rare species, occurring amongst white rata[10] blossoms in February. At present I have only taken three specimens, _viz._, two in Wellington and one in Nelson. The transformations of all the Acroceridæ are as yet unknown. Family SYRPHIDÆ. _Syrphus ortas_ (Plate VII., fig. 3, 3a larva, 3b pupa). Very common everywhere from September till May, or even later, when specimens may be often seen basking in the winter sunshine. The larva (3a) is a most useful insect to gardeners as it destroys an immense number of aphides, those noxious little insects that commit such fearful ravages on many valuable plants (see Hemiptera, page {57}120). In general appearance this larva resembles a small green slug, with the skin much wrinkled, and bearing at its extremity a short thick tube, which is probably the respiratory apparatus, the four lunate holes situated at its apex being no doubt the spiracles. These insects grow very slowly, occupying several weeks to attain maturity. Their mode of capturing the aphides is very curious, and is, briefly, as follows:--The larva lies in the midst of a number of aphides, and it occasionally happens that some of them crawl over it. On feeling an aphis touch its back the larva instantly darts out its long, pointed head and strikes its prey with the apex, which is enveloped in a quantity of very sticky mucus constantly ejected from the mouth. On the aphis being thus captured the larva withdraws its head into the hinder segments of its body and devours all the juicy portions of the aphis, whose dry skin is afterwards thrown aside. When full-grown it slowly shrinks up and changes into the pupa shown at Fig. 3b. In this state it is not protected by any kind of cocoon, but lies amongst the refuse of the aphides, near the stem of the plant. The fly emerges in a fortnight or three weeks' time, and is very fond of hovering over and sucking honey from the flowers, but the females may be often noticed running about plants, probably in search of a suitable place to oviposit.[11] For an account of _Scolobates varipes_, a species parasitic on the present insect, I refer to page 39. Family SYRPHIDÆ. _Eristalis cingulatus_ (Plate VII., fig. 2). This conspicuous insect occurs occasionally in glades in the forest about January, but is by no means common. It is very fond of the white rata flowers, where it may be {58}taken, if anywhere. Its life-history is at present unknown, but no doubt resembles that of the following insect. Family SYRPHIDÆ. _Helophilus trilineatus_ (Plate VII., fig. 1, 1a larva, 1b pupa).