Homalopoda, Howard, 1894

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 : 53-54

Genus HOMALOPODA Howard

Homalopoda Howard in Riley, Ashmead & Howard, 1894:90-91. Type species: Homalopoda cristata Howard , by monotypy.

Female. Overall length about 0.8-2.5mm.

Body generally dark brown to black with a metallic sheen; legs mostly dark brown with white to pale orange areas; fore wing infuscate with at least one pair of hyaline spots and usually with a hyaline spot in the middle; hind wing hyaline.

Head triangular in profile, tangent of frontovertex (occipital margin to top of scrobes) forming an angle of about 55-90°with that of face (top of scrobes to mouth margin); head varying from 2.5-7.7X wide as frontovertex; occipital margin sometimes rounded, but usually sharp with a bristle or scale-like seta behind posterior ocellus; area adjacent to eye and occipital margin usually with a small, indistinct, oval depression; area between eye above scrobe usually with a fairly conspicuous line of silvery setae; scrobes shallow, not sharply margined, broadly ∩-shaped; interantennal prominence dorsally rounded; scape varying from slightly broadened and flattened, about 3-6X as long as broad; flagellum slender, funicle 4-segmented, segments subcylindrical and usually all longer than broad and subequal in length, rarely some segments transverse, clava 3-segented, slightly curved downwards, apex rounded; malar sulcus absent; mandible with one tooth and a broad truncation or with 4 teeth, rarely with only 3 teeth (see below), a socketed peg present near ventral margin.

Pronotum hardly visible behind head, posterior margin strongly emarginate medially; pronotum with transversely elongate, imbricate-reticulate to polygonally reticulate sculpture that is a little shallower than that in ocellar area; mesoscutum with very similar sculpture to that on pronotum, notaular lines absent; axilla with slightly deeper, transversely elongate, polygonally reticulate to imbricate-reticulate sculpture; scutellum flat dorsally with very fine, regular, punctate-reticulate sculpture that is clearly deeper than sculpture on mesoscutum, side and apex completely smooth and shiny; apex of scutellum with 2 pairs of scale-like setae arranged regularly in a line or 1 pair of strong bristles (second pair sometimes present, but not arranged regularly and well in advance of apical pair); fore wing about 2.4-2.5X as long as broad; apex of fore wing without a hyaline spot; postmarginal vein usually much shorter than stigmal vein, rarely nearly as long; mesopleuron enlarged but posterior margin not quite reaching level of posterior margin propodeum, falling short by about diameter of propodeal spiracle.

Gaster with hypopygium not reaching apex; syntergum shorter than mid tibia to slightly longer with apex broadly truncate to acute; paratergites absent; ovipositor slightly exserted, the exserted part shorter than mid tibial spur.

Male. Overall length about 1.2-1.5mm.

Similar in general habitus to female but for hyaline wings, lack of paired setae or bristles on occipital margin and structure of antenna and genitalia; head largely metallic, thorax similar but more dull; head in profile not triangular, about 2.5X as high as deep with tangent of frontovertex forming an angle of about 90° with the face; frontovertex with fine punctate reticulate sculpture; scape attached a little above lower eye margin, about as long as distance of torulus from mouth margin, about 2.5X as long as broad; funicle 2-segmented, segments longer than broad, F1 more than 2X as long as F2; clava entire and longer than funicle; scutellum flat with fine punctate-reticulate sculpture, vertical side and apex smooth and shiny; fore wing with marginal vein about 3.5X as long as broad, about 1.5X as long as stigmal vein or postmarginal vein; phallobase elongate, about as long as mid tibia; digiti about 3X as long as broad and each with a single apical hook.

DISTRIBUTION. Central and southern Caribbean, Sri Lanka and India (possibly introduced).

HOSTS. Primary parasitoids of armoured scale insects ( Hemiptera : Diaspididae ).Also reported as a parasitoid of soft scales ( Hemiptera : Coccidae ) but this record requires confirmation.

COMMENTS Homalopoda aibeus sp.nov., described below, may be misplaced in Homalopoda because it has only 3 teeth in the mandible. However, other characters generally agree with placement in this genus.

Homalopoda is close to Pseudhomalopoda , Caenohomalopoda , and Plagiomerus , all four genera belonging to the Habrolepidini and having a 4-segmented funicle, 3-segmented clava and mandible with one tooth and a broad truncation or four teeth. It can be separated from Plagiomerus because the flagellum is relatively long and slender, not clavate, the fore wing is infuscate, there is a line of silvery setae between the eye and scrobal area and the postmarginal vein is shorter than the stigmal vein. In Plagiomerus the flagellum is clavate with at least 2 or 3 transverse segments, there is no line of silvery setae between the eye and scrobal area, the fore wing is hyaline and the postmarginal vein of the fore wing is at least as long as the stigmal vein. Caenohomalopoda has the forewing infuscate, but the funicle segments are relatively short and the pronotum is subtriangular in dorsal view clearly visible behind the head, with the posterior margin only weakly concave, whereas in Homalopoda the pronotum is only narrowly visible behind the head and the posterior margin is strongly emarginate medially. Of the other named genera, Pseudhomalopoda is the closest to Homalopoda and could be considered synonymous but species of Pseudhomalopoda have a distinct, well-defined, hyaline spot at the wing apex, whereas in Homalopoda there is a pair of opposite subapical, hyaline spots or the whole apex is slightly paler than proximal parts of the wing. Pseudhomalopoda also has a much shorter funicle compared to Homalopoda especially in the type species ( prima ) where the flagellum is distinctly slightly flattened with all funicle segments transverse.

IDENTIFICATION. 10 species known, including 9 described as new below. For description of Homalopoda cristata Howard , see Noyes (1979)