Insects of Britain and Ireland: the families of Hymenoptera

DELTA home

L. Watson and M. J. Dallwitz


Chalcid Wasps.

Adults minute, or small. Insects associated with plant galls, or not associated with galls.

Head. Antennal segments 11 (with the club regarded as 3-segmented). Antennae geniculate.

Thorax. Pronotum short, not extending back to the tegulae. Pronotum wide and quadrate, almost as wide as the (often coarsely punctured) mesoscutum. The mesepisternum not enlarged to obscure the mesepimeron (and the mid-tibial spur rarely larger than the hind one). Cenchri absent. Wings not folding longitudinally. Fore-wings without a pterostigma; with very reduced venation (reduced to a proximal submarginal vein, which becomes marginal distally before giving off the stigmal vein); combining greatly reduced venation with a conspicuous, blind-ending stigmal vein. Closed fore-wing cells 0. Submarginal cells 0. Discoidal cells 0. Hind-wings without closed cells. The hind coxae not conspicuously larger than the front ones. Fore tibiae with a curved spur. Hind femur not toothed below; with a clear trochantellus. Hind tibiae not curved around the femora; without specialised spurs. Tarsi 5 segmented.

Abdomen. The abdomen with a marked basal constriction. Visible abdominal segments not highly metallic. Ovipositor of females visibly protruding; adapted for piercing.

Larvae. Larvae legless or the legs vestigial; phytophagous (many), or parasitic on hosts selected by the mother (many, including egg parasites of Orthoptera, and parasites of gall-forming Diptera and Hymenoptera), or predacious, or parasitic on hosts selected by the mother and predacious (some social parasites living in nests of bees and wasps); when associated with galls, primary inducers of galls, or parasitic on other gall occupants, or predacious on other gall occupants.

General comments. The life styles and ecology extraordinarily varied. Differing from Chalcididae mainly in having a non-toothed and usually small hind femur, and from the more generalized Pteromalidae in the structure of the pronotum and propodeum.

British representation. Species in Britain about 90; Eurytoma, Systole, Sycophila, Tetramesa.

Classification. Suborder Apocrita; Series Parasitica; Superfamily Chalcidoidea.

Illustrations. • Sycophila biguttata (Cooperian Decatoma: B. Ent. 345). • Sycophila biguttata (detail: B. Ent. 345). • Sycophila biguttata (dissections: B. Ent. 345). • Sycophila biguttata: B. Ent. 345, legend+text. • Sycophila biguttata: B. Ent. 345, text cont.. • Eurytoma abrotani, male: Stephens 1846.

To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. Insects of Britain and Ireland: the families of Hymenoptera. Version: 16th May 2016.’.