The Steel Blue Sawfly, _Perga dorsalis_, is slightly over 1 inch in length; is of a deep metallic blue, marked on face and thorax with bright yellow, and has stout reddish brown wings; the smaller male has the upper surface of the abdominal segments clothed with silvery pubescence. _Perga kirbyi_ is dark reddish brown, similar in form and size to the last species; _Perga lewisii_, a much smaller yellowish brown insect, flattened on the dorsal surface, is common about Sydney upon the foliage of the “blood-wood” (_Eucalyptus corymbosa_), where she lays her eggs in the leaf in a double row, and stands over them until the tiny larvae hatch out and are able to move away; while thus occupied you can pick her up, but she will not move away, but raise her wings and fight like a hen over her chickens. Though this is our commonest species, and I have taken hundreds of females, I have never seen a male. _Perga cameronii_ is like the last species, but larger, with more distinct markings on the back; it is found on the Blue Mountains. In the Genus _Pterygophorus_ about 10 species are described; they are much smaller insects, with bright metallic blue colours marked with reddish yellow; the male has the antennae produced into a comb or feathery structure, those of the female are formed of short rounded joints. The larva is a dull olive green creature covered with small warty tubercules; the head is broad, and the abdomen tapers off into a slender pointed tail; it has seven pairs of abdominal legs. It feeds upon the foliage of _Leptospermum_, wild dock and other plants, and when full grown bores into dead wood, pupating in a rounded oval cell. The Ringed Sawfly, _Pterygophorus cinctus_, ½ an inch in length, is dark blue marked with deep reddish orange on the thorax, with a ring round the centre and tip of the abdomen of a similar colour; the wings are marked and clouded with black. [Illustration: Plate XI.--HYMENOPTERA. Family TENTHREDINIDAE. 1. _Pterygophorus cinctus_ (Klug). 2. _Pterygophorus cinctus_ (Klug), Antenna ♀. 3. _Pterygophorus cinctus_ (Klug), Larva. 4. _Philomastix glaber_ (Froggatt). 5. _Philomastix glaber_ (Froggatt), Antenna. 6. _Philomastix glaber_ (Froggatt), Larva.] [Illustration: _Plate XI.--HYMENOPTERA._] The Pale Coloured Sawfly, _P. interruptus_, slightly larger, has the thorax marked with orange yellow, and the abdomen deeply blotched with the same colour, forming interrupted bands on the sides; both these species are taken upon flowers in the summer months.