Torymus roboris (Walker 1833)

A member of the family Torymidae, this wasp is parasitoid of cynipid wasps.

The common gall hosts of this species are; Biorhiza pallida sexual. The flight times for this wasp is september.

The female wasp measures in at 2.8-4.1mm, excluding ovipositor, with an average of 3.4mm.
The head is a dark purple and smooth with a pattern of pale hairs. The eyes are medium to large and dark in colour with large brown ocelli. The antennae are dark bronze with a long orange scape, and a small pedicel that is marked with orange. There is one ring and 7 funicular segments, which are tapered and well seperated.
The dark metallic purple thorax has traces of green and deep full length notaulices. The tegulae are testaceous leading to the wings which are clear but have a brown tinted appearance due to the deep brown hairs. The veins are also deep brown. The legs are all brilliant orange except for the rear coxae which is part brown. There are 5 tarsel segments.
The gaster (abdomen) is testaceous at the front which shades into dark purple for the rest and has pale hairs. The ovipositor sheaths are longish, about 79% body length, and dark with bronze tints.

The male is about 2.2mm in length.
The head is a dark with purple notes and pale hairs. The eyes are large and dark in colour with translucent pale ocelli. The antennae are heavy and all bronze with a long reticulated scape, and a round pedicel. There is one ring and 7 funicular segments.
The dark metallic purple shot thorax has deep full length notaulices and the tegulae are testaceous leading to the wings which are clear. The veins and hairs are also mid density and the post marginal vein is short. The legs are yellow with dark markings on the coxae. There are 5 tarsel segments.
The gaster (abdomen) is dark neutral bronze brown with some purple tones and dirty orange at the front and on the sides.

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

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