About 50 species have been described from Australia; Smith listed and described a number of new species (British Museum Catalogue Hymenoptera 1855): Saussure described several in the same year (Memoires de la Societe de Physique, &c., Geneve), and later on others in the Annals of the Entomological Society of France 1858. In 1864 he and Sichel monographed the family: Smith described 8 more four years after: and Kirby going through the British Museum Collections in 1889 revised the Genera and added another to our list. _Discolia soror_ is our commonest shining black species; the female measures over 1 inch in length, and is easily identified by its beautiful, iridescent, opaque, dark blue wings. It may be often seen in our gardens on the flowers or hovering in numbers over a dead stump, looking for beetle larvae in which to deposit its eggs. _Scolia fulva_ is our largest species; the female measures up to 1½ inches in length, and is broad in proportion; it is black and reddish yellow, but so thickly clothed with coarse reddish hairs that it is more the latter tint; and the semiopaque wings are reddish brown. This species is figured and described by Gray in Griffith’s Animal Kingdom 1832. _Scolia radula_ is a smaller black species, under 1 inch in length; the head, apex of thorax, base of abdomen and most of the under-surface are clothed with grey hairs, but the hind margin of the head and dorsal surface of abdomen are clothed with reddish brown; the latter is orange yellow above, but marked with black at the base and tip. [Illustration: =Fig. 52.=--Life History of a Flower Wasp. 1. _Dielis formosa_ (Guérin). ♀. (1a.--Life size.) 2. „ „ Larva. 3. Pupal Cocoon, showing opening whence the wasp has emerged. (“Agricultural Gazette,” N.S.W.)] _Dielis 7-cincta_, one of our commonest species, often clustering in numbers on flowering shrubs in the gardens, was described by Fabricius, and is the male of _Dielis (Scolia) formosa_ which was not described till 1846 by Guérin. The male, ⅔ of an inch in length, is very slender in form, of a general black colour, clothed with fine grey hairs, and marked with light yellow on the head and thorax, with five broad bands of the same colour on the body. The female, under 1 inch in length, is black, with the abdomen marked on the upper surface with reddish yellow somewhat variable in its distribution, and clothed with reddish brown hairs, thickest on the head and thorax. This insect has been found in Queensland destroying the underground grub of the Sugar-cane Beetle (_Lepidoderma albo-hirtum_). Family 17. Sand Wasps. POMPILIDAE.