Hobbya stenonota (Ratzeburg 1848)

Hobbya stenonota has a synonym and was at one time called H. kollari. It is a parasitoid of the family Pteromalidae. As such it parasitises many members of the gall forming family of Cynapidae such as; Andricus kollari agamic, Aphelonyx cericola agamic and Biorhiza pallida sexual galls. The flight times of this wasp are from march through to september.

The female measures from 1.5-2.9mm with an average of 2.1mm head and body.
The head is over sized and dark meatllic gold green in colour and hairy. The face has fanned striae radiating out to the face and cheeks and is patterned by small reticulations. The eyes are largish and dark netral with toning in, and the ocelli are dark brown. The antennae have 2 rings and 6 funicular segments which are tranverse and brassy in colour. They are stout, short and tapered with dark sensillae and short, pale, decumbant hairs. The pedicel is short and fat whereas the dull yellow scape is long and set deep into the head.
The thorax is very dark metallic green and hairy with the notaulices incomplete. The tegulae are dark straw coloured and lead to the wings which are clear with mid neutral brown veins and neutral hairs. There is a wide marginal vein with a slight break (which is difficult to see) between the marginal and sub marginal veins. The stigmal vein is longish, with a visable sharp stigma. The legs have metallic reticulated coxae and femora with contrasting yellow trochanter, the rest being a pale translucent yellow and dark claws. There are 5 tarsi.
The gaster (abdomen) has the first segment a polished dark metallic green with the rest being a dark coppery bronze. It is heavily triangular from the side and is narrow but high with some faint microsculpture and is hairy at the edges and in bands across. The ovipositor sheaths are not visable.

The male measures 1.5-2.2mm averaging out at 1.8mm
The head again is oversized, reticulated dark metallic bronzey green and hairy with fanned striae radiating out to the face and cheeks. The eyes are largish and neutral brown, dark toning in with large pale ocelli. The antennae have 2 rings and 6 funicular segments which are brassy in colour. They are slightly longer than female antennae and slightly tapered with dark sensillae and short, pale, decumbant hairs. The pedicel is darker than the female and the dull yellow scape is set deep into the head.
The thorax is metallic bronzy green and hairy with the notaulices incomplete and barely visible. The dark neutral brown tegulae lead on to the wings which are clear with pale veins and neutral hairs on a transparent and wide marginal vein. A slight break (barely visible) between the marginal and the sub marginal vein. It has a longish stigmal vein with a visible sharp stigma. The legs have metallic reticulated coxae and dark brown femora tinged with metallic, yellow trochanter and joints with the rest being a biege/yellow and dark claws. There are 5 tarsi.
The gaster appears tiny and is pointed from above and from the side very thin. It is a shiney golden bronze and is hairy.

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

top of page