Hypomecus WESMAEL

A. M, 2009, Illustrated key to the tribes of subfamilia Ichneumoninae and genera of the tribe Platylabini of world fauna (Hymenoptera, Ichneumonidae), Linzer biologische Beiträge 41 (2), pp. 1317-1608 : 1502-1503

23. Hypomecus WESMAEL

Hypomecus WESMAEL 1844 - Mem. Acad. Brux.: 111.

Type species: Mesoleptus quadriannulatus GRAVENHORST (= Hypomecus albitarsis WESM. ) Hypomecus: TOWNES 1951 - Hymen. of A. North of Mexico: 181.

Hypomecus: HEINRICH 1962 - Syn. Nearct. Ichn. Sten.: 794-796.

Hypomecus: TOWNES et al. 1965 - Cat. Reclass. East. Pal. Ichn.: 514.

Type species: Hypomecus tylus UCHIDA

Hypomecus: HEINRICH 1974 - Ann. Zool. Wars. 32 (8): 193-195.

D i s t r i b u t i o n: Holarctic, Oriental Region.

I n t r o d u c t i o n:

It is isolated genus, distinct from other genera by number of unusual characters. It is presented by only one species, spread in Nearctic, Palaearctic and Oriental Regions without any geographical variations. The two structural peculiarities of the genus do not coincide with the general diagnosis of the tribe Platylabini : form of petiolus, which is not flattened at the base and not wider than height and slender and elongated form of abdo- men. On the other hand, structure of a head, convex clypeus, thin mandibles and even form of apex of abdomen of female are pointed on relationship with Platylabini . This position is also supported with the biological fact (by parasitism on Geometridae ).

Hypomecus , in addition is characterized by the peculiar morphology of scutellum square from above, with long slanting part, laterally carinated by slight carinae with shagreen vertical surface with dense microsculpture.

M o r p h o l o g y:

F l a g e l l u m: Of females bristle-shaped, long and very slender, ventrally flattened, but not widened beyond middle, strongly attenuated toward apex. Flagellum longer by length than front wing and slightly shorter than body length. Flagellum of males with pronounced broadly-oval tyloides.

H e a d: Head contour narrowed downwards, with gradually narrowed downwards long genae; temples from above strongly, but roundly narrowed behind eyes. Occipital carina meeting with hypostomal carina before mandible base, lower part of hypostomal carina visible from lateral; mandibles sharply narrowed behind base, with form character to tribe; clypeus convex, transversal, with straight front margin; antennal cavities large, deep, without tooth between antennal fossae; ocellar triangle slightly elevated. Face and clypeus shining without microsculpture; clypeus punctured in different degree, middle field of face slightly wrinkled.

T h o r a x: Transverse furrow of pronotum not interrupted by keel; pronotal ridge not thickened; epomiae sharp; pronotal base sharply uniformly curved. Mesonotum strongly convex, only just longer than width; notauli distinct in front third; surface of mesonotum very densely punctured, with developed microsculpture; subalarum thin, sharpened; sternauli weak, marked in front third; scutellum considerably elevated above postscutellum, square from above, with gradual slant, almost with equal length from apex to basal (scuto-scutellar) furrow and from apex to postscutellum, laterally carinated to middle; vertical surface of scutellum and postscutellum with dense microsculpture, shagreen. Hind margin of metanotum with triangular projections. Propodeum from lateral gradually slanting backwards; horizontal part shorter than length of area posteromedia; area superomedia usually elongated, rounded from front, of males often square; costulae atrophied; coxal carina not developed; apices of areae dentiparae angularly protrude; spiracles rather large, elongated.

L e g s: Slender and long.

W i n g s: Areolet big, from quadrangular to almost pentagonal with very narrow base, symmetrical; nervulus interstitial. Length of front wing shorter than body length.

A b d o m e n Abdomen long, narrowed to apex, fusiform, second tergite elongated; sheath of ovipositor only just visible protrude behind apex of abdomen. First tergite from lateral gradually curved; petiolus at base not flattened, smooth from lateral, ventrally not bordered by carinae, from above broadened to rectangular postpetiolus with distinctly expressed, but not bordered by carinae middle field. Gastrocoeli superficial, long; thyridia very large, oblique, reach to borders of tergite, far removed from base of second tergite, with narrow interval between them; lunulae large, distinct. Hypopygium of female compressed from lateral, long, strongly sharpened, protrude behind apex of last tergite.

C o l o r a t i o n: Mainly black. Legs reddish-brown, hind tarsi with white annulus.

S i z e: 8-10 mm.