Strigenia, Noyes, 2023

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 : 171-172

Genus STRIGENIA gen.nov.

Type species: Strigenia laras sp.nov. Gender feminine.

Female. Length about 1.8mm.

Body generally dark brown to black with a weak metallic sheen, scutellum almost matt; scape pale orange; flagellum orange-brown to pale brown; legs largely dark brown with pale orange areas; wings hyaline, fore wing venation brown with submarginal vein partially yellow; hind wing venation yellow.

Head about 3-4X as wide as frontovertex; occipital margin acute, sharp, not carinate; vertex with a slender, shiny bottomed groove, about as long as posterior ocellus, adjacent to eye margin extending from near occipital margin to about level with middle of posterior ocellus; frontovertex with 3 or 4 shallow, piliferous punctures in middle below anterior ocellus; scrobes shallow, but well defined, more or less ∩-shaped, meeting, antenna attached below eye margin, upper margin of torulus below lower eye margin, torulus slightly less than its own length from mouth margin; scape hardly broadened, widest about middle and about 4X as long as broad; pedicel conical, about 1.5X as long as broad, funicle segments subcylindrical, subequal, subquadrate, becoming slightly larger distally, linear sensilla on all segments except F1; clava 3-segmented, slightly wider than funicle; sutures subparallel, sensory area very slightly enlarged giving apex a rounded appearance; eye slightly overreaching occipital margin, clothed in very inconspicuous, short setae that are clearly shorter than diameter of facet; malar sulcus virtually absent, but present dorsally, very shallow and inconspicuous; mandible virtually tridentate, with 2 acute teeth and a slightly concave truncation; palp formula 4-3.

Thorax with pronotum short, narrowly visible behind head with posterior margin strongly concave; posterior margin of mesoscutum medially slightly produced posteriorly so that medially it partially covers the axilla; scutellum convex; mesopleuron slightly expanded posteriorly, but not quite extending past posterior margin of propodeum so that in profile the propodeum and hind coxa meet narrowly; fore wing about 2.3X as long as broad, with a line of setae dorsally in distal half of costal cell and more or less 2 lines ventrally; submarginal vein with parastigma hardly broadened and not downcurved; junction of submarginal vein and marginal vein with a hyaline break; marginal vein about 4X as long as broad, about 1.5X as long as stigmal vein and 2X as long as postmarginal vein; uncus developed, with only 3 campaniform sensilla in a line; basal cell with a triangular naked area, linea calva entire, filum spinosum present, comprised 2 or 3 modified setae; mid tibial spur about as long as basitarsus; mesopleuron not quite reaching posterior margin of propodeum, falling short by about diameter of spiracle, narrowly separated from base of gaster by propodeum and hind coxa; propodeum medially about 0.1X as long as scutellum, about 15 silvery setae outside spiracle and about 20 on side above hind coxa.

Gaster about as long as thorax; hypopygium reaching about halfway along gaster, about 2.5X as broad as long with posterior median invagination about 0.4X as deep as length of hypopygium; ovipositor slightly exserted, a little longer than mid tibia; second valvifer without any subapical setae; gonostylus free; outer plate narrow, subtriangular.

Male. Unknown.

DISTRIBUTION. Costa Rica.

HOSTS. Unknown.

COMMENTS. I am unable to place Strigenia confidently within the current encyrtid classification of the Encyrtinae . As the key suggests, Strigenia may be closest to Caldencyrtus . The two genera can be separated using the characters given in the key. In addition the posterolateral corner of the propodeum is quite rounded in Strigenia and the apex of the stigmal vein has only 3 campaniform sensilla, whilst in Caldencyrtus the posterolateral corner of the propodeum it is usually sharp with a short, tooth-like projection and the apex of the stigmal vein has 4 campaniform sensilla.

The presence of a shiny bottomed groove adjacent to the occipital margin between the occipital margin and posterior ocellus, tridentate mandible and the presence of only three campaniform sensilla in a line at the apex of the stigmal vein together suggest that it may be related to Mahencyrtus . There is a slight superficial similarity in habitus, but Strigenia differs in having similar, fine, coarse polygonally reticulate sculpture of rounded cells on the mesoscutum, axilla and scutellum, the fore wing only about 2.3X as long as broad and completely lacking an expanded parastigma, and the syntergum much broader than long and shorter than the mid tibia. In Mahencyrtus the sculpture of the mesoscutum is composed of rounded cells contrasting with the deeper, strongly logitudinally elongate sculpture of the scutellum, the fore wing is at least about 2.8X as long as broad with the parastigma is conspicuously expanded, and the syntergum is much longer than broad and longer than the mid tibia.

Of other genera superficially similar to Mahencyrtus , Strigenia differs from both Prionias and Georynus in having the apex of the clava more or less rounded, similar fine polygonally reticulate sculpture on the mesoscutum and scutellum and mesopleuron not quite reaching level with the posterior margin of the propodeum. In both Prionias and Georynus the apex of the clava is obliquely truncate, the sculpture on the scutellum is clearly much deeper than on the meoscutum and the mesopleuron reaches level with the posterior margin of the propodeum. Strigenia also differs from Prionias in having the mandible with two teeth and a straight truncation, the apex of the syntergum rounded and the hypopygium strongly transverse with the posterior margin biconvex and with a deep, median invagination, whereas in Prionias the mandible is distinctly tridentate with the upper tooth truncate, the apex of the syntergum has a median tongue-like projection and the hypopygium is about as long as broad, strongly V-shaped with the posterior margin acute and with only a very small, shallow median invagination. Strigenia further differs from Georynus in lacking a pair of submedian, spherical gland-like structures on the anterior margin of TII of the gaster and the syntergum is apically rounded and broader than long and distinctly shorter than the mid tibia. In Georynus the anterior margin of TII of the gaster has a pair of submedian, spherical gland-like structures and the syntergum is apically acute and about as long as broad and at least about as long as the mid tibia