Caenohomalopoda, Tachikawa, 1979

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 : 80-82

Genus CAENOHOMALOPODA Tachikawa

Caenohomalopoda Tachikawa, 1979:169 . Type species Pseudhomalopoda shikokuensis Tachikawa , by original designation.

Female. Length about 1.1-1.6mm

Body slightly dorsoventrally flattened, generally dark with a metallic sheen, head largely dark blue or dark green mixed with a purple, coppery or brassy sheen; thorax green, blue-green, coppery, purple and brassy; antenna brown; palpi white; coxae brown; legs otherwise mostly dark brown, with tarsi, base of mid femur and most of mid tibia white or very pale yellow; wings infuscate with a radial pattern of hyaline areas, venation mostly brown; gaster with a metallic green, blue or purple sheen with brassy and coppery reflections.

Head about 3.0X as wide as frontovertex, triangular in profile with frontovertex moderately flat, forming an angle about 60° with face at top of scrobes; occipital margin rounded, a conspicuous long scale-like seta present on margin behind each posterior ocellus; posterior ocellus separated from occipital margin by about 2X its own diameter; ocelli forming an angle of about 90°; frontovertex with relatively deep, punctiform, polygonally reticulate sculpture; antenna with scape triangular, broadened and flattened, about 2.4-2.8X as long as broad; funicle 4-segmented, segments strongly transverse to hardly longer than broad; clava nearly as long as funicle or longer, 3-segmented, sutures parallel, apically pointed or rounded, sensory area at apex only; eye slightly overreaching occipital margin, clothed with inconspicuous short setae; malar sulcus absent; mandible with four, unequal teeth. lowest tooth longest, and a distinct ventral peg; palp formula 4-3

Thorax with pronotum broadly exposed behind head, subtriangular in dorsal view, posterior margin weakly concave; pronotum and mesoscutum with imbricate-reticulate to polygonally reticulate sculpture; mesoscutum quite flat; scutellum convex, dorsally with a triangular flat area, this area with punctate-reticulate sculpture much deeper than sculpture on mesoscutum, side and apex broadly, completely smooth and shiny; scutellum about 1.3X as broad as long, apex with a pair of erect scale-like setae; fore wing about 3X as long as broad; costal cell ventrally with a single complete line of setae and dorsally with a line of setae in its apical one-third or so; submarginal vein with a subapical hyaline break, parastigma slightly swollen, without a single, longer erect seta; marginal vein about 3X as long as broad, about 5X as long as postmarginal vein and 2X as long as stigmal vein; linea calva interrupted by 1 or 2 lines of setae; filum spinosum present as a line of 5 slightly stouter setae; mesopleuron posteriorly more or less reaching level with posterior margin of propodeum; propodeum short, at most a single seta outside spiracle and some irregular linear sculpture in lateral one-third of dorsal part of propodeum extending posteriorly as troughs and ridges towards hind coxa.

Gaster with hypopygium reaching about half way to two-thirds towards apex, transverse, subrectangular, posterior margin medially invaginate; syntergum slightly longer than mid tibia, with apex angular; ovipositor slightly exserted 0.1-0.3X as long as gaster, nearly 2X as long as mid tibia and about 4X as long as gonostylus.

Male. Length about 0.7-1.0mm.

Generally very similar to female but for structure of antenna or genitalia, frontovertex about half head width; flagellum mostly white or very pale yellow, F1 sometimes dusky, apex of clava often dark brown; antenna with scape slightly broadened, about 3.5X as long as broad, pedicel about 1.5X as long as broad, funicle 2-segmented, both segments much longer than broad; clava very long, about 6-7X as long as broad and from slightly longer than pedicel and funicle combined to only about as long as F1, apex pointed, with a short finger-like projection; flagellum clothed in setae that are a little less than 0.5X diameter of segments; fore wing hyaline and with postmarginal vein about as long as stigmal vein or slightly longer.

DISTRIBUTION. India, Vietnam, China, South Korea, Japan, Indonesia, Guam, USA (Hawaii) ( Noyes, 2019) and central America (see below).

HOSTS. Parasitoids of diaspidids associated with bamboo, e.g. Froggattiella penicillata (Green) and Odonaspis secreta (Cockerell) , ( Hemiptera : Diaspididae ) (see Noyes, 2019). A record of C. shikokuensis (Tachikawa) as a parasitoid of Pseudococcus Westwood is probably erroneous and needs to be confirmed ( Ge & Shi, 1995).

COMMENTS. Caenohomalopoda is closest to Plagiomerus Crawford , Pseudhomalopoda Girault , and Spaniopterus Gahan , all four genera belonging to the Habrolepidini and having a 4-segmented funicle. It differs from Spaniopterus by having the clava 3-segmented and subcylindrical segments whereas in Spaniopterus the clava is 2-segmented and the flagellum is strongly flattened. Pseudhomalopoda is superficially the most similar to Caenohomalopoda but can be distinguished by having the mandible with one tooth and a broad truncation, two pairs of scale like subapical setae on the scutellum and a relatively short pronotum that has a strongly emarginate posterior margin medially which, if the pronotum is measured along the mid-line, is not more than about one-eighth as long as the mesoscutum. In Caenohomalopoda the mandible has four teeth, there are only one pair of scale-like setae on the scutellum and the pronotum is subtriangular with a weakly concave posterior margin which, if measured along the mid line is nearly half as long as the mesoscutum. Plagiomerus has mandibles with four teeth as in Caenhomalopoda, but differs from Caenohomalopoda in having a short pronotum as in Pseudhomalopoda and hyaline fore wings, whereas in Caenohomalopoda the fore wings have a distinct infuscate pattern.

IDENTIFICATION. 12 World species: see Fatima & Zeya, 2022 (8 Indian species); Singh, 2004

(6 World species); Tachikawa et al., 1981 (4 World species); Trjapitzin & Sharkov, 1992 (5 World species); Zhang & Huang, 2006 (8 World species).