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).

Key to Costa Rican species of Cercobelus

(Females and males)

1. Clava 3-segmented (e.g. Figs 1626, 1642, 1659, 1670) (females) ..................................2

- Clava entire (e.g. Figs 1631, 1643, 1652, 1664) (males) .............................................. 11

FEMALES

2 (1) Antenna (Figs 1626, 1640, 1655, 1656) with F1 without linear sensilla, at least a little shorter than F2 ..................................................................................................... 3

- Antenna (Figs 1659, 1670, 1678, 1680, 1685, 1693) with F1 with linear sensilla, at least as long as F2 ......................................................................................................... 5

3 (2) Fore wing (Fig. 1627) completely hyaline; syntergum (Fig. 1634) with numerous, dense pegs on apex, rasp-like .............................................. epimetheus sp.nov. (p. 611)

- Fore wing (Figs 1635, 1650) with a distinct infuscate area around stigmal vein; syntergum (Fig. 1653) not apically rasp-like ......................................................................... 4

4 (3) Hind tibia dark brown with a well-defined, basal, white band; scape (Figs 1640-1642) more than 4X as long as broad; antennal pedicel at least 1.8X as long as broad; hypopygium (Figs 1645, 1646) completely longitudinally divided medially, about as long as broad with slender, anterior apodemes long and slender ....................... ....................................................................................... adrastea sp.nov. (p. 613)

- Hind tibia entirely brown without a well-defined, basal, white band; scape (Figs 1655, 1656) less than 4X as long as broad; antennal pedicel not more than 1.6X as long as broad; hypopygium (Figs 1648, 1649) transverse, only partially longitudinally divided medially, at least 1.5X as broad as long and without slender anterior apodemes ............................................................ isara Noyes & Hanson (p. 614)

5 (2) Antenna (Figs 1559, 1670, 1678) with F4 transverse or subquadrate, less than 1.2X as long as broad ........................................................................................................ 6

- Antenna (Figs 1680, 1685, 1693; Hab. 251) with F4 at least 1.2X as long as broad ..... 8

6 (5) Apical half of fore wing (Fig. 1662) with a distinct elongate, infuscate, wedge-shaped area ..................................................................... sithon Noyes & Hanson (p. 615)

- Apical half of fore wing (Figs 1672, 1675) generally very weakly infuscate or hyaline .. ...............................................................................................................................7

7 (6) Fore wing with marginal vein punctiform (Fig. 1671), not longer than broad; spiracle on propodeum relatively small and separated from anterior margin by about its own diameter; hind tibia dark brown with a well-defined, white, basal band ............... ........................................................................................ pleiades sp.nov. (p. 616)

- Fore wing with marginal vein more than 1.5X as long as broad (Fig. 1676); spiracle on propodeum large and separated from anterior margin by about 0.3X its own diameter; hind tibia entirely brown without a well-defined white band ................. ........................................................................................ tartarus sp.nov. (p. 617)

8 (5) Fore wing with marginal vein (Fig. 1681) about 5X as long as broad .............................. ............................................................................ ulixes Noyes & Hanson (p. 619)

- Fore wing with marginal vein (Figs 1689, 1691; Hab. 251) punctiform, not longer than broad .................................................................................................................... 9

9 (8) Fore wing (Fig. 1688) hyaline with only a small infuscate area adjacent to stigmal vein; hind wing about 3X as long as broad................................ phanes sp.nov. (p. 620)

- Fore wing (Fig. 1691; Hab. 251) with infuscate area extending at least half way across wing below stigmal vein; hind wing more than 3.5X as long as broad ..............10

10 (9) Scape and flagellum concolourous amber-testaceous; width of head equal to length of pedicel and flagellum combined; fore and mid femora mostly dark brown; propodeum with submedian, longitudinal carinae .................................................. ........................................................................ godoyae Noyes & Hanson (p. 621)

- Scape pale orange, clearly paler than brown flagellum; width of head less than length of pedicel and flagellum combined; fore and mid femora mostly pale orange; propodeum with a single median longitudinal carina ............................................. .......................................................................... daphne Noyes & Hanson (p. 622)

MALES

11 (1) Fore wing completely hyaline; head in facial view with eyes kidney-shaped with inner margins strongly concave (similar to Fig. 1630) ...... epimetheus sp.nov. (p. 611)

- Fore wing with at least area adjacent to stigmal vein infuscate; head in facial view with eyes not kidney-shaped, inner margins weakly concave ................................... 12

12 (11) Fore wing with a weak median, longitudinal, infuscate streak distad of apex of venation; costal cell with two lines of ventral setae .......... sithon Noyes & Hanson (p. 615)

- Fore wing hyaline distad of apex of venation; costal cell with only a single line of setae ventrally in distal half ........................................................................................ 13

13 (12) Hind tibia entirely brown without a well-defined, basal, white band ................................ ............................................................................. isara Noyes & Hanson (p. 614)

- Hind tibia dark brown with a well-defined, basal, white band ..................................... 14

14 (13) Flagellum clothed in setae that are more than 2X as long as diameter of segments, mesoscutum bright metallic green, scutellum coppery ........................................... ....................................................................................... adrastea sp.nov. (p. 613)

- Flagellum clothed in setae that are shorter than diameter of segments; mesoscutum and scutellum hardly shiny, more or less black ........ ulixes Noyes & Hanson (p. 619)