This genus comes next to Smicra, which has the greatest development of the peculiar characters of the family Chalcididae, such as the compact antennæ, the robust body, the large quadrate prothorax, and the much dilated hind thighs. In all these characters this family agrees with Leucospidae, from which it totally differs in the structure of the abdomen, and the two families have a supremacy of structure which is not wholly shared by any other in the tribe Chalcididae.