Among the most remarkable is the “Blue Ant,” _Diamma bicolor_. In this case the female is most common; about Sydney I have caught scores of females, but so far have never taken a male. She measures 1 inch in length, and is of a rich metallic blue to purple colour, smooth and shining, the antennae and legs reddish brown. She is furnished with a fine pair of jaws and a powerful sting, more formidable than that of any ant, and when disturbed turns over on her back and shows fight with both jaws and sting. The male, much smaller in size, is black, with red legs and black tarsi; the wings are semitransparent with black nervures. The whole upper surface of head and thorax is rugose, and the insect very ant-like in general appearance. Mr. Roland Turner is at present engaged in working up the Australian Thynnidae at the British Museum, having his own and my collection of specimens to identify; probably this combined collection is the largest in existence, and contains an immense number of sexed specimens collected in the field, as we have both spent a great deal of time over these typical Australian insects. Family 16. Hairy Flower Wasps. SCOLIIDAE These insects are easily distinguished from the Thynnidae in being thickset hairy wasps; both sexes are furnished with wings in which the neuration is distinct at the base, but the nervures fade out before they reach the tips; the thorax is broad, rounded in front, with a very short pedicle attaching it to the stout abdomen. The legs are stout, compressed, very hairy, and spiny, with one stout spur on the tibiae of the middle pair of legs well adapted for burrowing. The males are easily distinguished from the females in being more slender in form, with longer straight antennae (in the latter sex short, thickened, and curling round the sides of the head); and the legs are slender, with fewer spines. Several species are plentiful about the Sydney gardens and bush, where they can be easily captured on the flowers. In observations made by earlier entomologists, their life history seems to have been confused with those of the long legged sand wasps, which burrow in the ground and form regular nests provisioned with other insects and spiders; but the SCOLIIDAE form no true nest; the female burrows into the ground or under logs, where she finds the larvae or white grubs of the larger lamellicorn beetles, on which she deposits a single egg, first carefully stinging the beetle grub (according to Fabre, the French naturalist, who studied the habits of several European species). The young wasp hatching out attaches itself to the helpless grub in such a manner that it does not injure the vital organs, and by the time it has devoured its host it is ready to pupate, spinning a brown silken cocoon which fits into the cavity first occupied by the unfortunate beetle grub; when fully developed it digs its way up to the surface.