The great Genus _Megachile_ contains the leaf-cutting bees, so called from the curious habit they have of cutting circular pieces out of the leaves of growing plants with which they line their nests; these are sometimes built in excavations in old walls, or dead wood, or simply constructed like a cigar under stones. About 30 species have been described from Australia; the two largest are _Megachile monstrosa_, figured in Brenchley’s “Cruise of the Curaçoa,” published in 1873; and _M. blackburni_, described by me from specimens obtained from Central Australia by the Elder Exploring Expedition. _Megachile mystacea_, a medium sized species found in Queensland and Northern Australia, is also recorded from India; it is black, with the head and face clothed with silvery hairs, and the whole of the abdomen covered with rich reddish brown pubescence; while _M. pictiventris_ has the hind margin of the thorax clothed with silvery hairs, the apical half of the under-surface with reddish brown hairs which extend to form a fringe round the extremity. _M. chrysopyga_ is a native of Tasmania and Victoria. I found a nest of this species under a stone in the latter State, which could be lifted up bodily without breaking. It was about the shape and length of an ordinary cigar, and consisted of about nine cells containing the larvae. These cells, like a series of shallow thimbles, were enfolded in the outer shell of looser leaf. The Genus _Coelioxys_ comprises a number of curious bees that in general appearance are so very like the “leaf cutters,” that a French naturalist having bred one out of a Megachile’s nest described it as the male form of the species. They are now known to be parasitic in the nests of these bees in Europe, so that the similarity in form may be of great protective value to them. They differ chiefly in the form of the abdomen, which in the males is produced into forked spines at the extremity, and in the females into a sharp point. I have two undetermined species in my collection from Queensland obtained some years ago, but until last year the presence of this group had not been recorded from Australia. Cockerell recorded (1905) two species from this country; _Coelioxys albolineata_, measuring about ⅓ of an inch in length, comes from Queensland, and is of the usually grey and brown tints.