Perilissus holmgreni Habermehl, 1925

Verheyde, Fons, Hoekstra, Paul, Libert, Pierre-Nicolas, Meijer, Hilco, Ketelaere, Augustijn De, Vandaudenard, Thibaud, Belgers, Dick & Brosens, Edwin, 1880, Two hundred and five ichneumonid wasps reported for the first time in Belgium and the Netherlands (Hymenoptera: Ichneumonidae), Belgian Journal of Entomology 122, pp. 1-142 : 67-68

Perilissus holmgreni Habermehl, 1925 (Fig. 33 A–B)

Much like the abovementioned species, P. holmgreni has its mesopleuron and mesoscutum predominantly coriaceous. Its pterostigma is dark brown, however, and its metasoma is black apically, (partly) testaceous basally (Fig. 33 A). The lateromedian longitudinal carinae on the propodeum are faint posteriorly. Its mandibles are testaceous, but the tips are black (Fig. 33 B). P. holmgreni seems to be a genuinely rare species with few reports in Europe. Even (unidentifiable) pictures of anything resembling it superficially were not found, while ichneumonids caught with light traps are often photographed and placed on citizen science portals. Our specimen was caught in the vicinity of some of Belgium’s most exceptional nature reserves consisting of rare limestone grasslands. The parasitic relations are unclear. Among the supposed hosts are the sawfly Allantus cinctus (Linnaeus, 1758) (Symphyta: Tenthredinidae )

and the crabronid wasp Crossocerus podagricus (Vander Linden, 1829) ( Apocrita : Crabronidae ), but this combination seems to be very unlikely and conceivably other hosts are still present (HEDWIG, 1950; STARKE, 1956).

First report for Belgium; unreported in the Netherlands.

MATERIAL EXAMINED:

BELGIUM: • 1 ♀; Nismes , Viroinval (NA); 50°04’04”N 4°34’19”E; 7/vii/2020; T. Vandaudenard leg.; coll. TV; light trap; G. Broad det. (ObsID: 204815687); Fig. 33 A–B .