An account is given of the structure of the gaster and mechanism of the ovipositor in the females of the Eurytomidae. The histology and the possible functions of the components of the reproductive systems are described and its bearing on their phylogenetic relationships of the group discussed.
The female gastral sclerites and ovipositor mechanism in the Eurytomidae have a number of distinctive characters. Within the family there is a progressive evolution of a coiling of the ovipositor associated with accommodating a longer shaft within the abdomen. Each ovary has three ovarioles and the shape of the egg is constant. There are two pairs of colleteral glands, a well developed “venom” system and a distinctive spermatheca.
The family has affinities with the Torymidae and may be close to the ancestral chalcid stock.