Torymus cyaneus

A member of the family Torymidae, this wasp is parasite of cynipid wasps. Far from being the usual Torymid parasitoid of its host however, this wasp is actually an inquiline and develops on the gall tissue competing with the original cynipid gall maker, which is killed later (Askew, 1961a; 1965b). Synonyms; Syntomaspis cyaneus

The common gall hosts of this species are; Andricus quercuscalicis agamic, Cynips divisa agamic, C. longiventris agamic, C. quercusfolii agamic. The flight times for this wasp are from may to july.

The female wasp measures in at 2.6-4mm, excluding ovipositor, with an average of 3.4mm.
The head is a metallic green with a leathery sculpture and plenty of white hairs. The eyes are large and red large red ocelli. The antennae have are grey brown and covered in pale hairs. The scape is dirty orange and metallic on the side. There is one ring and 7 funicular segments.
The polished metallic green thorax has little scuplture and pale hairs.It has deep full length notaulices. The tegulae are blue green coloured leading to the wings which are clear and have colourless hairs and brown veins, with a very short stigmal vein. The legs have green metallic coxae and femora, brown tibia and yellow tarsi, of there are 5 segments.
The gaster (abdomen) is a brilliant metallic green and blue with variable amounts of testaceous beneath. The ovipositor sheaths are mid length (about 61% of body length) and dark.

The male is mm averaging at 2.mm in length.
The head is bright metallic blue green with a leathery sculpture and long white hairs. The eyes are large and red with red ocelli. The antennae are dark and there is one ring and 7 funicular segments covered in pale longitudinal sensillae.
The thorax is a bright metallic green and blue with traces of red and long white hairs. Deep full length notaulices, like the female. The tegulae are blue green, and the wings are clear, with pale veins and hairs. The stigmal vein is short with a strong stigma and a short but wide post marginal vein. The legs have metallic green coxae, femora and part of the tibia. The joints are pale and the basitarsus is yellow but the rest are dark. There are 5 tarsel segments.
The dark gaster has varying amounts of metallic green and rich blue. The first sement is smooth but the rest have a central line of long golden hairs as well as cross striae.

More detailed descriptions and identification keys are available from Robin Williams at the British Plant Gall Society.

top of page