green weed, although they are perhaps carnivorous, feeding on the rotifers and other animalculæ, which swarm in the water where they are found. {101}With regard to the method employed by the young larva in constructing, and subsequently enlarging, its case, I can give no positive information, although it is undoubtedly made of a viscous fluid, secreted by the insect, which hardens when exposed to the water; this secretion is no doubt analogous to the silk of caterpillars, which always exists in the form of a gummy fluid before being spun. When about to change, the insect fixes its case down by four ligaments, two at each end, the extremities of these being firmly fastened to a stone; it then closes the small aperture, and constructs a curious arch-shaped partition, of dense material, a short distance from the broad end (Fig. 3b). In about a week's time the larva is transformed into a pupa, having the limbs, &c., free from the body but incapable of motion. The fixing down of the case prior to the change may be easily performed from each of the apertures, which are no doubt left open till the last for this purpose. Before the final transformation the pupa breaks through the partition at the broad end of the case and rises to the surface, the imago (Fig. 3) ascending a blade of grass to dry and expand its wings. The little exuvia of the pupa may be often noticed floating on the water, and the empty cases are very conspicuous on the sides of a glass aquarium, where the insects generally fix them down when in captivity. Family HEMEROBIIDÆ. _Stenosmylus incisus_ (Plate XIV., fig. 2). This lovely insect is figured as an example of this family, being found occasionally in the New Zealand forest, but is rather scarce as a rule. I regret that nothing is at present known of its transformations. {102}Family Sialidæ. _Chauliodes diversus_ (Plate XIV., fig. 1, 1a larva, 1b pupa). During still warm weather, from December till March, this large insect is frequently observed flying lazily over water at dusk, when it may be readily captured with the ordinary net. Its larva is aquatic, living under stones in running streams, where it devours large quantities of Ephemeræ and other insect larvæ, which are always abundant in those situations. It is very ferocious and will bite violently when disturbed, being furnished with a pair of powerful mandibles. The curious filaments on each side are gills, and it will be noticed that they are situated exactly where the spiracles of the perfect insect afterwards appear (see Fig. 1a).