Prochremylus Brues, 1933

Genus Prochremylus Brues, 1933 View in CoL

Prochremylus Brues, 1933: 26 View in CoL ; Shenefelt 1975: 1154; Belokobylskij 2014: 380; Yu et al. 2016.

Type species. Prochremylus brevicornis Brues, 1933 View in CoL

Diagnosis of the genus ( Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 ). Head not depressed, transverse. Vertex weakly convex, granulate-reticulate or almost smooth. Occipital carina present, distinct, below fused with hypostomal carina near base of mandible. Ocelli medium-sized. Eyes large, oval, glabrous. Temple (dorsal view) medium length or short, curved posteriorly, transverse diameter of eye distinctly larger than submedial length of temple (lateral view). Face convex. Malar space medium length; malar suture rather distinct. Mandibles short. Maxillary palpus short, perhaps 4-segmented; labial palpus short and perhaps 2-segmented. Antenna rather thickened, filiform, with 11–12 antennomeres. Scape elongated and relatively narrow, without any transformations. Pedicel long and weakly widened, about half as long as scape. First flagellomere long, not depressed, subround in dissection, straight. Second flagellomere wider than first one, subcylindrical, relatively long. Penultimate flagellomere relatively narrow and short, shorter than apical flagellomere; the latter weakly acuminate and without apical spine.

Mesosoma not depressed. Pronotal neck short. Mesoscutum highly and subperpendicularly elevated above pronotum, granulate-rugulose. Notauli present and perhaps complete, but sometimes weakly visible. Prescutellar depression (scutellar sulcus) relatively long, with distinct medial carina, rugulose. Scutellum convex. Mesopleuron medially widely smooth. Precoxal sulcus present, oblique, short, about half of mesopleuron length below, rather wide, straight, rugulose-crenulate. Propodeum weakly convex (lateral view), with areas delineated by coarse carinae; lateral tubercles absent.

Wings. Fore wing faintly infuscate; pterostigma rather long and wide. Radial (marginal) cell wide, not shortened. Metacarp (1-R1) longer than pterostigma. Radial vein (r) arising before middle of pterostigma. First medial abscissa (1-SR+M) present and weakly curved. Discoidal (discal) cell petiolate anteriorly, petiole (1-SR) long. Second radiomedial (submarginal) cell relatively short and pentagonal. Recurrent vein (m-cu) short, strongly oblique, postfurcal to first radiomedial vein (m-cu), distinctly convergent posteriorly with basal vein (1-M). First mediocubital vein (M+CU1) well sclerotised and straight. Nervulus (cu-a) postfurcal. Parallel vein (CU1a) subinterstitial to second mediocubital vein (2-CU1). Brachial vein (CU1b) present and closed brachial (first subdiscal) cell distally. Brachial (subdiscal) cell relatively wide, closed subperpendicularly at or weakly behind level of recurrent vein (m-cu). In hind wing, radial vein (SR) weakly sclerotised and not pigmented. Nervellus (cu-a) present and closed rather long submedial (subbasal) cell. Recurrent vein (m-cu) mainly unsclerotised, curved, weakly antefurcal.

Legs relatively narrow and rather long. Hind coxa elongate, suboval, without ventro-basal tubercle, about half as long as propodeum. Hind femur relatively long, narrow or weakly thickened. Hind tibia slender. All tarsal claw small and simple.

Metasoma. First metasomal tergite relatively short and wide, convex, sculptured, with distinct, high and complete dorsal carinae, with distinct sublateral carinae along margin of tergite, dorsope small. Second and third tergites weakly sclerotised, weakly punctate or smooth, without separated laterotergites, spiracles situated upper inflection between dorsal and lateral parts of tergite, with fine or distinct and almost straight second suture; second tergite distinctly longer than third one. Ovipositor weakly curved, in apical part perhaps without visible dorsal and ventral armament. Ovipositor sheath relatively short, less than half of metasoma, slender, rather densely setose.

Comparative diagnosis. The Eocene genus Prochremylus Brues is similar to the extant genus Chremylus Haliday, 1833 based on the fore and hind wing venation, and structure of metasoma and propodeum. Chremylus was originally placed in the subfamily Pambolinae (previously tribe Pambolini in Exothecinae ), but was then placed in the tribe/subtribe Chremylini /Chremilina ( Hellén 1957; Belokobylskij 1993). Only on the basis of recent molecular phylogenetic analysis ( Jasso-Martinez et al. 2022) this genus was finally transferred to the subfamily Hormiinae and was nested in the clade together with Acanthormius from the tribe Lysitermini . However in a recent publication ( Chen & van Achterberg 2019) the Chemylini was even considered as a tribe of subfamily Rogadinae without any justification.

The genus Prochremylus Brues differs from Chremylus Haliday in having the propodeum without postero-lateral processes (with distinct thick processes or tubercles in Chremylus ), precoxal sulcus distinct and crenulate (absent or almost absent and smooth in Chremylus ), the first abscissa of mediocubital vein (M+CU) of hind wing not shorter than second abscissa (1-M) (distinctly shorter in Chremylus ), temple mainly smooth (entirely densely and coarsely rugose-granulate in Chremylus ), femur of hind leg not curved basally and smooth (rather distinctly curved basally and densely granulate-reticulate in Chremylus ), and the first metasomal tergite relatively narrow (very wide in Chremylus ).