Promethes Förster 1869

Klopfstein, Seraina, 2014, Revision of the Western Palaearctic Diplazontinae (Hymenoptera, Ichneumonidae), Zootaxa 3801 (1), pp. 1-143 : 79-81

Promethes Förster 1869

Liopsis Förster 1869

Promethus Thomson 1890

Type species. Bassus sulcator Gravenhorst 1829

Diagnosis. Promethes species have a very smooth and shining face, punctate or impunctate, with two vertical impressions arising from the tentorial pits, a character that they only share with most Sussaba species. Promethes species can readily be distinguished from Sussaba by having the spiracle of the second tergite above the lateral fold.

Face smooth and shining, sometimes weakly punctate around seta roots, with strong vertical impressions, in females entirely black or with a yellow central patch, in males entirely yellow. Clypeus with apical margin thin, with a basal elevation that makes it flat or concave in profile. Antenna with apical flagellomeres wider than long or longer than wide, in males with linear, narrow tyloids, without long setae. Mesoscutum with notauli comparatively long, reaching one third of length of mesoscutum, sometimes shallow; smooth and shining with very weak punctures in P. bridgmani and P. sulcator , more densely punctate in remaining species, yellow shoulder marks present or absent; mesopleuron usually entirely smooth and shining, weakly punctate only on lower half but sometimes ( P. nominiguis ) densely punctate and rugose sculpture; epicnemial carina complete ventrally. Propodeum with a full set of carinae enclosing basal, petiolar and lateral areas; propodeal spiracle inconspicuous; scutellum usually carinate to middle. Fore wing areolet absent; hind wing often with 1 ( P. bridgmani and P. sulcator ) but sometimes with 2 or 3 ( P. melanaspis , P. nigriventris and P. nominiguis ) basal hamuli. Hind tibia orange to brown or white with a dark apex. Female metasoma dorsoventrally depressed, or apically weakly compressed in P. melanaspis and P. nigriventris ; tergites without transverse impressions and with hind margins convex. First tergite with median dorsal carinae not reaching apex of tergite but often longitudinally striate. Second tergite with spiracle dorsal, above lateral fold, third tergite with spiracle below or behind the fold. Metasoma orange on tergites 2 to 5 or 6, or entirely black, in males often with yellow markings. Ovipositor sheaths 0.3 times as long as hind tibia, slender, slightly tapered and fully enclosing ovipositor, slightly compressed, with inconspicuous setae ventrally and apically. Males with tergites 9 and 10 fused as a syntergum, sternite 9 longer than wide, as a single lobe, outer corners rounded.

Phylogeny. Promethes is part of the Sussaba genus group. Many molecular and morphological characters support this placement, for instance the unilobate male ninth sternite. The four Western Palaearctic species were confirmed to be monophyletic by molecular methods; they share a three-base-pair deletion (or lack the corresponding insertion) in the mitochondrial NADH1 gene not found in any other diplazontine genus.

Distribution. Holarctic, Oriental and Neotropical. The fifteen species currently recognized in this genus are mostly Holarctic, but four species have been recorded from the Oriental region, and one from the Neotropics. Further sampling of the Afrotropical and Australasian regions might well expand our current knowledge about the distribution of this genus.

Biology. While nothing is known about the host relations of most species, P. sulcator had been reared from a variety of hosts of the tribe Syrphini , thus showing a comparatively broad polyphagy.

Key to species

1. Antenna orange or brown, long and slender, with 22 or more flagellomeres; first flagellomere more than 5 times as long as wide. Hind tibia orange or yellow, apex sometimes dark. Metasoma in females and often also in males marked with orange on at least some of tergites 2 to 5............................................................................ 2

- Antenna black or sometimes brown, stouter, with 22 or fewer flagellomeres; first flagellomere at most 4.5 times as long as wide. Hind tibia white or yellow with a dark subbasal and apical band. Metasoma in females entirely black, in males often with yellow markings...................................................................................... 3

2. Malar space with a deep subocular groove ( Fig. 21 A). Scutellum yellow-marked............. Promethes bridgmani Fitton

- Malar space without subocular groove ( Fig. 21 B). Scutellum black.................... Promethes sulcator (Gravenhorst)

3. Second metasomal tergite rugose, matt, wider than long. Mesopleuron distinctly punctate over most of its surface. Petiolar area of propodeum filled with carinulae. Females with metasoma dorsoventrally depressed to apex...................................................................................................... Promethes nomininguis Dasch

- Second metasomal tergite smooth and shining at least on apical half, basally with longitudinal wrinkles, longer than wide. Mesopleuron with punctures weak, distinct at most on lower half. Petiolar area of propodeum mostly smooth, with carinulae restricted to its margins. Females with metasoma laterally compressed............................................ 4

4. Scutellum with a large yellow blotch covering most of its surface. Mesoscutum with large yellow shoulder marks which usually expand over notauli. Basal area of propodeum usually more than 2.5 times wider than long, with apical carina often partly reduced ( Fig. 22 A)......................................................... Promethes nigriventris (Thomson)

- Scutellum usually black but sometimes marked with yellow on anterior part, especially in males. Mesoscutum without or at most with small yellow shoulder marks which do not expand over notauli. Basal area of propodeum usually less than 2 times wider than long, with apical carina strong ( Fig. 22 B)............................... Promethes melanaspis (Thomson)

Figures

FIGURE 21. Faces of Phthorima species showing the grove in the malar space and the shape of the clypeus. A. Phthorima picta. B. Phthorima compressa. Scale bars represent 500 µm.

FIGURE 22. Propodea of Promethes species showing carination and shape of the different areas. A. Promethes nigriventris. B. Promethes melanaspis. Scale bars represent 500 µm.