Syrphophilus Dasch 1964a

Klopfstein, Seraina, 2014, Revision of the Western Palaearctic Diplazontinae (Hymenoptera, Ichneumonidae), Zootaxa 3801 (1), pp. 1-143 : 98-99

Syrphophilus Dasch 1964a

Type species. Bassus bizonarius Gravenhorst 1829

Diagnosis. The genus Syrphophilus can be recognized by the combination of the following characters: fully carinate propodeum, yellow inner orbits of females and often males, weak indications of transverse impressions at least on the first tergite, and the lack of a fore wing areolet or of notauli. Some males of S. scabriculus and S. tricinctorius might show some indications of notauli; I thus also included a cross-reference for the genus Syrphophilus in the Tymmophorus species key.

Face coriaceous and matt, without vertical impressions, in females black with yellow inner orbits and sometimes a central spot yellow, in males similar or often entirely yellow. Clypeus with apical margin thin, with a basal elevation that makes it covex in profile, broad and short. Antenna with apical flagellomeres wider than long in females but longer than wide in males, without tyloids and without long setae. Mesoscutum without notauli (rarely indicated in male S. tricinctorius ); usually smooth and shining and weakly to strongly punctate but sometimes entirely coriaceous and impunctate; yellow shoulder marks usually present; mesopleuron variously sculptured, ranging from entirely smooth and shining and punctate on lower half to coriaceous and matt; epicnemial carina complete ventrally. Propodeum with a full set of carinae enclosing basal, petiolar and lateral areas; propodeal spiracle inconspicuous; scutellum only carinate basally. Fore wing areolet absent; hind wing with 2–4 basal hamuli. Hind tibia orange or brown with apex often dark. Metasoma dorsoventrally depressed with hind margins of tergites convex; tergites with subapical transverse impressions usually weakly indicated on first and sometimes second tergite. First tergite with broadly separated or without median dorsal carinae. Second and third tergites with spiracles dorsal, above lateral folds. Metasoma black, often with yellow or orange markings, or orange on tergites 2–5. Ovipositor sheaths 0.3 times as long as hind tibia, laterally compressed, tapered and fully enclosing ovipositor; basally smooth, apically with dense and conspicuous setae. Males with tergites 9 and 10 fused as a syntergum, sternite 9 about 1.5 times wider than long, weakly emarginated to form two lobes, their outer corners with an acute angle.

Phylogeny. Monophyly of Syrphophilus is well supported by both morphological and molecular data. The relationships between the remaining genera of the Diplazon genus group, however, are not well resolved, especially concerning the genus Tymmophorus . It thus remains to be shown what the sister genus is of Syrphophilus .

Distribution. Holarctic and Oriental. This genus only includes six species, the Nearctic Syrphophilus ichneumonoides (Provancher) and the five Holarctic species discussed here. Two of the latter have even been reported from the Oriental region, and this genus thus has a very high proportion of species with multi-regional distributions.

Biology. Syrphophilus bizonarius and S. tricinctorius have been reared from a range of Syrphinae , mostly of the tribe Syrphini (e.g. Thirion 1994).

Key to species

1. Sternaulus very strongly impressed on anterior half of mesopleuron ( Fig. 25A ), usually with transverse carinulae in the impression. Metasoma marked with orange at least on hind margins of tergites 2 and 3. Tergites 1–3 usually distinctly punctate on a smooth and shining background, more rugose in males.......................... Syrphophilus bizonarius (Gravenhorst)

- Sternaulus visible but never as strongly impressed, without transverse carinulae ( Fig. 25B ). Metasoma black with yellow or sometimes with orange markings.Tergites usually more rugose and coriaceous and matt, only rarely smooth and strongly punctate (only in Syrphophilus stibarus Momoi )................................................................. 2

2. Antenna with at least 19 flagellomeres in both sexes. Metasoma in females entirely black or with yellow spots apico-laterally on tergites 2 to 3 or 4, in males black with yellow apical bands on tergites 1 or 2 to 4 or 5. Femora usually entirely orange, male face usually entirely yellow, and scutellum at least marked with a yellow apical spot.. Syrphophilus tricinctorius (Thunberg)

- Antenna with 16–19 flagellomeres. Metasoma in both sexes entirely black or with orange or yellow hind margins. Femora often marked with black below, male face often with yellow inner orbits and a central yellow spot, scutellum with or without yellow markings...................................................................................... 3

3. Mesopleuron, mesosternum and scutellum mainly orange, metasoma black or with diffuse dark red coloration. Coxae, trochanters and legs entirely orange.................................................. Syrphophilus asperatus Dasch

- Mesosoma black, scutellum black or yellow-marked. Coxae black or yellow, trochanters yellow....................... 4

4. Mesopleuron, mesoscutum and tergites 1 to 3 smooth and shining and strongly punctate...... Syrphophilus stibarus Momoi

- Mesopleuron impunctate but with weakly coriaceous areas; mesoscutum with smooth and indistinctly punctate areas laterally but coriaceous towards middle and along the lines extending the notauli; tergites strongly coriaceous and matt.................................................................................... Syrphophilus scabriculus (Holmgren)

Diagnosis. Fore wing length 4.5–5.3 mm. Antenna of both sexes with 16–18, usually 17 flagellomeres. Mesoscutum smooth and shining between weak but very dense punctures. Mesopleuron coriaceous and punctate over most of its surface. Sternaulus weakly impressed. Propodeum with a full set of strong carinae enclosing basal, lateral and petiolar areas, the areas with rugose sculpture. First tergite with median dorsal carinae strongly developed at least on basal half. Second and third tergites with punctures indistinct against the strongly rugulose or coriaceous background.

Figures

FIGURE 25. Sternaulus in Syrphophilus. A. Syrphophilus bizonarius with a very deeply impressed sternaulus. B. Syrphophilus tricinctorius with the sternaulus distinct but less deeply impressed. Scale bars represent 500 µm.