In the British Museum Catalogue of Neuroptera published in 1852, Walker gives only four species from Tasmania and Australia: _Leptocerus magnus_ and _L. oppositus_, which he describes from Tasmania, and _Plectrotarsus gravenhorsti_, described by Koller from Australia; the latter measures nearly an inch across the wings, and ⅓ of an inch in the body, and is of a general yellow tint, thickly clothed with yellow and black hairs; the fore wings are bluish black marked with white, yellow at the base and along the fore border; the hind wings are yellow but blackish toward the tips. _Monopseudopsis inscriptus_, described by Walker, is a larger fly, of a general black colour, with pale wings spotted with yellow, the hind pair clouded. The locality of this species is given as Australia. Order IV.--HYMENOPTERA. Bees, Ants and Wasps. This division contains an immense number of very interesting insects which, though generally known as bees, ants, and wasps, comprise many other just as important families; some are unfortunately popularly called flies, such as saw-flies, gall-flies, and ichneumon-flies, but all true flies have only one pair of wings. Hymenoptera are, with a few exceptions, furnished with two pairs of semitransparent membranous wings, sometimes shaded with black or yellow tints, devoid of hairs or scales, but traversed by stout nervures forming irregular cells; the hind pair are the smaller, and are furnished with a row of spines along the front margin capable of hooking into the hind edge of the fore pair, thus adding to their powers of flight. [Illustration: =Fig. 41.=--Diagram of the Head of a Wasp. _a_, eyes; _b_, clypeus; _c_, labrum; _d_, mandibles; _e_, ocelli; _f_, insertion of the antennae. (Redrawn from Cresson’s “Hymenoptera of North America.”)] [Illustration: =Fig. 42.=--Diagram of the Thorax of a Wasp. _a_, prothorax; _b_, mesothorax; _c_, scutellum; _d_, postscutellum; _e_, metathorax; _f_, tegulae; _g_, parapsidal grooves. (Cresson’s “Hymenoptera of N. America.”)] In a few anomalous groups we find the females wingless, such as _Thynnidae_, _Mutillidae_ and others; in some like the fig insects _Blastophaginae_, the males are wingless and blind; in the ants, while the males and females are winged, the bulk of the community consists of wingless workers forming a third sex or caste. [Illustration: =Fig. 43.=--Diagram of Fore-wing of a Bee (_Mellinus_).