Diplazon tetragonus
Creators: name: Klopfstein, Seraina
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Ichneumonidae
Diplazon
Diplazon tetragonus

description: Diplazon tetragonus (Thunberg 1824, Ichneumon)
Ichneumon hortorius Thunberg 1824
Ichneumon ustorius Thunberg 1824
Bassus tricinctus Gravenhorst 1829
Bassus nemoralis Holmgren 1858
Bassus concinnus Cresson 1868
Bassus albicoxus Provancher 1874
Bassus amoenus Provancher 1874
Diagnosis. Fore wing length 3.7–5.2 mm. Antenna in females with 16–17, in males with 16–18 flagellomeres. Face with punctures usually distinct from the background sculpture. Mesopleuron smooth and polished weakly punctate largely restricted to lower half. Propodeum with a full set of carinae enclosing basal, lateral and petiolar areas. Tergite 1 1.0–1.25 times as long as wide in females, 1.2–1.4 in males, tergite 2 0.6–0.75 in both sexes; tergites 2 and 3 mainly rugose and coriaceous, at most with some irregular punctures, especially on tergite 3, the area between the punctures not entirely smooth. Transverse impressions distinct on tergites 1–4. Metasoma dorsoventrally depressed.
Colouration of females. Antenna dark brown. Head and mesosoma black, face with yellow along inner orbits, without yellow central face patch, yellow on clypeus and mouthparts, hind corner of pronotum, tegula, subtegular ridge, shoulder mark, upper mesepimeron; scutellum at least with yellow tip, usually largely yellow. Legs and coxae orange, fore coxa usually dark at extreme base; femora orange; hind tibia black-white-black banded, sometimes apical band with an orange or orange-brown area, hind tarsus dark. Metasoma black.
Colouration of males. As in females but with yellow ventrally on scape and pedicel, antenna often orange below, yellow over entire face, spot on propleuron, epicnemium and part of mesosternum. Fore and mid coxae yellow, hind coxa mainly orange. Tergites 2 and 3 sometimes with light posterior margins, the colour of which can be light brown to orange but never entirely yellow or white.
Material examined. Holotype of Ichneumon tetragonus Thunberg: Sweden, no locality data. 1♂, at UU. Holotype of Ichneumon hortorius Thunberg: Sweden, no locality data. 1♂, at UU. Holotype of Ichneumon ustorius Thunberg: Sweden, no locality data. 1♂, at UU. Lectotype of Bassus nemoralis Holmgren: Sweden, Småland, leg. Boheman. 1♀, at NRM.
Austria (1), Denmark (1), Finland (7), France (1), Germany (8), Hungary (50), Norway (1), Russia (3), Spain (1), Sweden (>100), Switzerland (>100), Turkey (1), United Kingdom (70), USA (1).
Distribution. Holarctic and Oriental.
Figures. Metasoma ♀ (Fig. 7 B, 18A), hind wing (Fig. 11 D), fore wing (Fig. 12 C), clypeus (Fig. 12 G), hind tibia (Fig. 12 L).
Notes. This is a rather variable taxon and might not represent a single biological species. Several taxa have already been split from tetragonus in the past, e.g. D. scutatorius and D. pallicoxa, and it is possible that even the remaining taxon still consists of a complex of species.
description: Published as part of Klopfstein, Seraina, 2014, Revision of the Western Palaearctic Diplazontinae (Hymenoptera, Ichneumonidae), pp. 1-143 in Zootaxa 3801 (1) on pages 46-47, DOI: 10.11646/zootaxa.3801.1.1, http://zenodo.org/record/249944