The classification of the bees is still somewhat unsatisfactory. Latreille termed them MELLIFERA, honey gatherers, or ANTHOPHILA, lovers of flowers: Westwood and others, while keeping this as a group name, subdivided them into two large families, ANDRENIDAE, short-tongued bees, and APIDAE, long-tongued bees, dividing the last family into five smaller groups based upon their different structure and habits. The European bees have been since placed under six headings; while in Dalla Torre’s Catalogue dealing with the bees of the whole world, there are no less than fourteen sub-families. Most of our species have been described by Smith, in the British Museum Catalogue, Hymenoptera 1853; others in the Transactions of the Entomological Society 1862–68, and New Species, British Museum 1879. Cockerell (Ann. & Mag. Nat. History 1905) described a number of new species of our bees examined by him in the British Museum Collections, and added some interesting information on species already described; as many of these specimens were collected by Turner, Walker, and myself and sent to the British Museum, the Australian localities are given. None of the short-tongued bees store up honey, but form cells or burrows in the ground, walls, cavities in rocks, or the stems of plants, in which they form a row of cells or little chambers each containing an egg and sufficient bee bread for the development of the larva. Some of these bees are parasitic, and live at the expense of the industrious species, crawling into the open nests and laying their eggs upon the food supply of the rightful occupant; these are popularly known as “cuckoo bees.” The members of the Genus _Prosopis_ are handsome, shining black or steel blue bees, marked with bright yellow upon the face and thorax. With the additions that Cockerell has made to the list, nearly fifty species are described from Australia, and a number are common in the vicinity of Sydney. _Prosopis vidua_, our largest species, but considerably smaller than the honey bee, is found upon the crimson flowers of the bottlebrush (_Callistemon_). It has the head and thorax black, with a yellow spot on the face and the base of each fore wing; the abdomen is bright metallic blue. A smaller undetermined species may be often noticed hovering round and entering holes in the soft sandstone rocks where it appears to nest. _Prosopis metallica_, a shining black species, smaller than _P. vidua_, with face and shoulders broadly marked with yellow, was bred out of a row of half a dozen brown papery cocoons placed in an empty burrow formed in the branch of a wattle tree by the larva of some longicorn beetle. _Lamprocolletes plumosus_ and several other species of the genus frequent the flowers of the Leptospermum. It is a handsome dark brown bee, under ½ an inch in length. The abdomen has a metallic sheen, and the head and thorax are clothed with fine down.