Cercobelus, Walker, 1842

Noyes, John Stuart, 2023, ENCYRTIDAE OF COSTA RICA (HYMENOPTERA: CHALCIDOIDEA), 4 Subfamily Encyrtinae: tribes Arrhenophagini, Habrolepidini, Cerapterocerini, Cheiloneurini, Trechnitini, Cercobelini, Polaszekiini, Protyndarichoidini, Gahaniellini and Syrphophagini (part), mainly primary parasitoids and hyperparasitoids of Coccoidea and Psylloidea (Hemiptera), Taxonomic Monographs on Neotropical Hymenoptera (Oxford, England) 2 (11), pp. 1-921 : 608-609

Genus CERCOBELUS Walker

Cercobelus Walker in Haliday, 1842:vi. Type species: Encyrtus jugaeus Walker , by monotypy.

Female. Length about 1.1-2.8mm.

Body dark (brown or black) with a weak to moderate metallic sheen; fore wing hyaline or with infuscate areas.

Head oval or spherical in facial view with eye relatively small, not longer than minimum width of frontovertex or hardly so; inner eye margin slightly emarginate; occipital margin sharp from mandibular bases; antenna inserted close to mouth margin; scape about 3.7-6.3X as long as broad; funicle 4segmented; clava 3-segmented; malar sulcus absent; mandible with one very short tooth and a very broad, slightly oblique, sometimes concave truncation with a very finely serrate margin, rarely with 4 very short, obtuse teeth.

Mesoscutum without notaular lines; axillae broadly meeting medially; mid tibial spur very long and longer than basitarsus; fore wing about 2.4-2.5X as long as broad, with marginal vein varying from very short, almost absent, to about 5X as long as broad; postmarginal vein almost absent; setae in basal cell much less dense than in disc; hindwing 3-4X as long as broad.

Gaster somewhat elongate, normally longer than thorax, segments telescopic; hypopygium reaching apex of gaster, generally subtriangular, longitudinally divided and with distinct anterior apodemes, posterior margin sometimes produced as paired lobes medially (Figs 1679, 1686); ovipositor short and not more than 0.5X as long as mid tibia or hardly longer, with a unique, highly modified structure (see Figs 1632, 1638, 1653, 1658, 1669, 1677, 1684); outer plates of the ovipositor connected to enlarged, lateral, subapical lobes of syntergum (see Figs 1634, 1653, 1661, 1674, 1687).

Male. Length about 1.1-1.9mm.

Similar to female, but antenna usually with segments relatively slightly longer and clothed with setae that are longer than diameter of segments; clava entire; genitalia with aedeagus apically very acute and digiti distinct but relatively slender and apically armed with a pair of hooks.

DISTRIBUTION. Probabaly cosmopolitan but recorded from Europe, Africa, India, Indonesia, Australia and central America ( Noyes & Hanson, 1996; Noyes, 2019).

HOSTS. Cercobelus jugaeus (Walker) has been recorded as a primary parasitoid of Psyllopsis Löw ( Hemiptera : Liviidae ) (see Trjapitzin, 1989). A record of Psyche? crassiorella (Bruand, 1851) ( Lepidoptera : Psychidae ) as the host of the same species (Hansen et al., 2012) requires confirmation.

COMMENTS. Cercobelus can be separated quite easily from other genera of encyrtids by the combination of 4-segmented funicle, completely carinate occipital margin, entire mesoscutum and relatively elongate, uniquely structured telescopic gaster with a relatively short ovipositor. It is likely that the telescopic gaster is used to gain access to the nymphs of its host which live within leaf galls formed by their host food plant.

IDENTIFICATION. 12 described species known worldwide including those described as new below. See Noyes & Hanson, 1996 (5 Costa Rican species); Hayat, 2005 (1 Indian species); Trjapitzin, 1989 (1 Palaearctic species).