The BLASTOPHAGINAE are remarkable little creatures, for there is a very great difference in the sexes of the same species; the males, yellow or brown, wingless, and blind, are more like white ants in general appearance than chalcids. They breed in the interior of figs, and are numerous in Australia. Saunders (Trans. Ent. Soc. 1883) described our common species (_Pleistodontes imperialis_), found in the fruit of the Moreton Bay fig about March. The tiny male, ¹⁄₁₂ of an inch in length, is of the typical form and colour; the elongate, shining black female (which is figured) is so different a looking creature that it would never be taken for the opposite sex of the insect. Their life history and remarkable habits have been described in the Agricultural Gazette (June 1900). _Idarnis australis_, described in the same paper, is a slender, bright, metallic green wasp, with a long tubular ovipositor nearly twice the length of the whole insect, which she also uses by pressing it down against the fig to jump like an acrobat, as well as for puncturing the skin of the fruit. The insect I described as the supplementary male of _P. imperialis_, is, Dr. Mayr tells me, the wingless male of this species. Mayr in “_Neue Feigen-Insekten_ 1906” states that he finds that my identification is wrong and this is not the one named by Saunders but a new species which he calls _Pleistodontes froggatti_, and places my _Idarnis_ in his Genus _Sycoryctes_. [Illustration: =Fig. 46.=--_Dinoura auriventris_ (Ashmead). A parasitic Chalcid that destroys the gall-making coccids (_Brachyscelinae_) by devouring the females and pupating in the cavity. (Original, W.W.F.)] [Illustration: Plate XII.--HYMENOPTERA. Family CHALCIDIDAE. 1. Branch of Moreton Bay Fig (_Ficus macrophylla_). 2. Immature fig attacked by _Pleistodontes froggatti_ (Mayr), which are cutting their way into the fig. A female _Idarnis australis_ on the right-hand side of the fig. 3. Section of fig, showing insects in the centre. 4. _Pleistodontes froggatti_ (Mayr). ♀. 5. Cutting plate (mandibular appendage) used by the insect to cut into the fig. 6. Point of head, showing beak-like extremity, and the base of the mandibular appendage where attached to the head. 7. Wings of _Pleistodontes froggatti_ (Mayr). 8. _Pleistodontes froggatti_ (Mayr). ♂. 9. _Idarnes australis_ (Froggatt). ♂. 10. _Idarnes australis_ (Froggatt). ♀. 11. _Idarnes australis_ (Froggatt), Wings.] [Illustration: _Plate XII.--HYMENOPTERA._] * * * * *