Platylabus 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 : 1508-1509

25. Platylabus WESMAEL

Platylabus WESMAEL 1844 - Nouv. Mem. Acad. Sci. Bruxelles 18: 150, 153.

Type species: Platylabus rufus WESMAEL.

Platylabus: HEINRICH 1962 - Syn. Nearct. Ichn. Sten.: 698-754.

Platylabus: HEINRICH 1967 - Ichn. Stenop. of Africa 2: 396-397.

Platylabus: HEINRICH 1974 - Ann. Zool. Wars. 32 (8): 107-109.

Platylabus: HEINRICH 1977 - Ichn. Florida and Neigb. States 9: 273-274.

D i s t r i b u t i o n: Holarctic, Neotropical, Ethiopian and Oriental Regions.

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

The genus Platylabus is the largest by number of species genus of the tribe. The genus is characterized by the combination of following characters: 1 – spiracles of propodeum are elongated, longer than width, 2 – apices of areae dentiparae are always without apophysises and distinct teeth, 3 – area superomedia is without costulae, 4 – gastrocoeli are transverse with big thyridia, deeply impressed, each of them considerably wider than an interval (very rarely with equal breadth or even narrower than an interval) and 5 – abdomen at apex is always without white anal spots. The genus is close to the genera Cyclolabus HEINRICH with circular spiracles, Lamprojoppa CAMERON with strongly developed apophysises and conical scutellum and Dentilabus HEINRICH with developed costulae, teeth of propodeum and longitudinal impression between thyridia.

All species of the genus are almost exclusively the parasites of Geometridae . Only two European species are registered on another hosts (Drepana).

M o r p h o l o g y:

F l a g e l l u m: Of females long and slender, bristle-shaped, pointed toward apex, beyond middle flattened ventrally and sometimes slightly widened. Flagellum of males not nodose and not serrate (unlike of Pristiceros GRAVENHORST ), mainly without tyloides, rarely with rudimentary punctiform or bacilliform tyloides. Flagellum approximately equal by length to front wing and body length.

H e a d: Head contour from front narrowed downwards in varying degree. Vertex more often gradually oblique to low and sharply expressed occipital carina; occipital carina from above from strongly roundly impressed to ocelli (e.g. type species), to only just impressed, almost straight; temples from above narrowed in varying degree and rounded behind eyes, to strongly convex or almost linearly oblique, from short to long; occipital carina meeting with hypostomal carina on base or before base of mandible, not modified at lower part; mandibles usually strongly narrowed behind base with delicate teeth, from sharply narrowed behind base, to gradually narrowed behind base to apex and to uniformly narrowed to apex, lower tooth moved inside in varying degree; clypeus as rule transversal, convex, with straight front margin and rounded lateral corners, usually distinctly separated from face; clypeal foveae deep; labrum of various form, more often labrum not protrude from under clypeus; middle field of face expressed; antennal cavities distinct, tubercle between antennal fossae usually distinct; ocelli of normal size, ocellar triangle frequently elevated.

T h o r a x: Transverse furrow of pronotum not interrupted by keel; pronotal ridge not thickened, epomiae developed; pronotal base with gradual sinuous margin. Mesonotum convex, mainly slightly longer than width in middle, or of equal length and breadth; notauli usually developed only at base of mesonotum; subalarum normal, high; sternauli slightly impressed; scutellum moderately elevated, laterally carinated up to postscutellum, its horizontal part slightly convex, not conical. Hind margin of metanotum with triangular projections. Propodeum from lateral of broken type, or gradually slanted, horizontal part almost always distinctly shorter than vertical; area superomedia approximately square or rectangular; all carinae, with exception of costulae developed; areae dentiparae often with sharp corners but without true apophysises and strong teeth; spiracles elongated, more rarely short-oval, never small and circular.

L e g s: Slender. Hind tarsi usually shorter than tibia. Claws thin.

W i n g s: Areolet quadrangular, more often almost symmetrical; radius slightly curved, long; nervulus interstitial; membrane of wing hyaline. Front wing approximately equal to body length.

A b d o m e n Of females shortly-oval or broadly-oval, flattened, second tergite more often not longer than breadth; sheath of ovipositor usually slightly protrude. First tergite distinctly wider than height at base, from lateral usually with gradual passage to postpetiolus and distinctly carinated; middle field of postpetiolus from indistinct to distinct, irregularly wrinkled or almost smooth, not longitudinally striated. Gastrocoeli distinctly deeply impressed, usually transverse, with narrowed interval, of some species not distinctly transverse with rather wide interval; thyridia distinct; apex of females abdomen not pointed (truncated). Hypopygium long, sometimes from lateral protrude behind apex of last tergite.

C o l o r a t i o n: Basic color of body of most species black or red, without white or yellow pattern on abdomen, often in a little degree on head and thorax; of some species abdomen with marked by light-colored stripes and head and thorax more broadly marked by light-colored; abdomen without apical white spots; wings never strongly darkened.