Diphyus restitutor (Wesmael, 1859)

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 : 72-73

Diphyus restitutor (Wesmael, 1859) (Fig. 36 A–B)

Within the tribe of Ichneumonini (subtribe Amblytelina ), Diphyus spp. can be recognised by their robust appearance, (normal) mandibles with two teeth, postpetiole with striae or wrinkles longitudinally, rudimentary thyridia and metasoma without tergites 3–6 elongated ( VALEMBERG, 1983; TERESHKIN, 2011).

The species does not seem to be well described in recent literature. Therefore, we make an elaborate description based on BERTHOUMIEU (1895). It has been found hibernating by Tereshkin, but so far, no evidence on this aspect has been found for the Low Countries (VERHEYDE, in prep.). Its clypeus is truncated in both sexes, which are sexually dimorph. The females are predominantly black with a dark bluish hue. White are the banded (black) antennae, the frontal orbits and its scutellum. There are also at least two dorsolateral spots on the second and third tergite (thus four in total – at least), like in D. quadripunctorius (Muller, 1776) , and at least two spots on the apical segments (the penultimate one only covering more or less half of the tergite). Sometimes there is a third spot, barely visible. Its coxae and legs are completely black except for the tibiae, which are red brown, and the tarsi, which are infuscate, especially on the hind legs (Fig. 36 A). The males are also predominantly black, but have up to eight white dorsolateral spots, also covering the first and fourth tergite. Their antennae are completely black, but the pronotal collar and the subtegular ridge are sometimes marked with white. Their legs are yellow to orange instead of red brown. Their hind tibiae have a blackish band apically (Fig. 36 B). Approximately 15 mm. Hosts are unknown.

First report for the Netherlands; unconfirmed in Belgium.

MATERIAL EXAMINED:

THE NETHERLANDS: • 1 ♀; Heeze-Leende , Strabrechtse Heide (NB); 51°23’51”N 5°38’16”E; 17/vii/2013; T. Strabrecht leg.; field observation; J. Valemberg det. (ObsID: 105736665) . • 1 ♀; Terschelling (FR); 53°22’59”N 5°15’13”E; 16/vii/2019; L. Bot leg.; field observation; W. Pénigot & F. Verheyde det. (ObsID: 176411989); Fig. 36 A • 1 ♀; Renkum (GE); 51°59’48”N 5°44’45”E; 26/iv/2020; R. Majoor leg.; field observation; F. Verheyde det. (ObsID: 193594733) . • 1 ♂; Ospel , Groote Peel (LIN); 51°20’04”N 5°48’18”E; 18/vii/2020; J. Slaats leg.; field observation; F. Verheyde det. (ObsID: 196500973) . • 1 ♂; Asten , Groote Peel (NB); 51°21’05”N 5°48’22”E; 21/vii/2020; J. Slaats leg.; field observation; F. Verheyde det. (ObsID: 196759071); Fig. 36 B .