Insects of Britain and Ireland: the families of Hymenoptera

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L. Watson and M. J. Dallwitz


Including Aphelinidae, Eupelmidae, Signiphoridae, Thysanidae.

Chalcid Wasps.

Adults minute to small; 0.5–5(–9) mm long. Insects associated with plant galls, or not associated with galls.

Head. Antennae geniculate.

Thorax. Pronotum short, not extending back to the tegulae. The mesepisternum large, more or less covering the mesepimeron (and the mid-tibial spur usually enlarged). 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. 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 usually 5 segmented (occasionally 4?).

Abdomen. The abdomen with a marked basal constriction. Ovipositor of females visibly protruding, or not visibly protruding; adapted for piercing.

Larvae. Larvae with segmented legs; phytophagous, or parasitic on hosts selected by the mother (often on Hemiptera, and sometimes hyper-parasitic); when gall-associated, primary inducers of galls, or parasitic on other gall occupants, or predacious on other gall occupants.

General comments. This family comprises chalcids having the mid-leg modified for jumping.

British representation. Species in Britain about 200; nearly 80 genera, with Aphelinus, Copidosoma, Encyrtus, Eupelmus, Litomastix, Metaphycus, Microterys, etc., represented by numerous species.

Classification. Suborder Apocrita; Series Parasitica; Superfamily Chalcidoidea.

Illustrations. • Stenoceroides walkeri (Curtis): B. Ent. 596. • Stenoceroides walkeri (Curtis): B. Ent. 596, legend+text. • Stenoceroides walkeri (Curtis): B. Ent. 596, text cont.. • Encyrtus swederi (Vine Encyrtus: B. Ent. 395). • Encyrtus swederi (detail: B. Ent. 395). • Encyrtus swederi (dissections: B. Ent. 395). • Encyrtus swederi: B. Ent. 395, legend+text. • Encyrtus swederi: B. Ent. 395, text cont.. • Metaphycus melanostomatus, female: as Encyrtus punctipes, 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.’.