Tremex contractus Maa 1949
Creators: name: Shinohara, Akihiko
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Siricidae
Tremex
Tremex contractus

description: Tremex contractus Maa, 1949
(Figs 1E, 3J, 4G, 5F, M, 6E, 8E, F, 9E, 10J, 11E, 12B, G, 13; Tables 1–4)
Tremex contractus Maa, 1949: 161; Takeuchi, 1955a: 2, 7; Takeuchi, 1962: 3, 10; Okutani, 1971: 18; Smith, 1978: 96; Watanabe, 1986: 31; Abe & Togashi, 1989: 558; Xiao et al., 1992: 55; Sakamoto, 1997: 28; Togashi, 1997: 1; Lee et al., 1998: 300; Anonymous, 2004: 169; Togashi, 2006: 938; Yoshida, 2006: 105; Nakahama et al., 2006: 5; Matsumoto et al., 2009: 27; Taeger et al., 2010: 107; Ushirokita et al., 2012: 32; Anonymous, 2014; Lee et al., 2019: 14; Naito, 2019: 19; Naito, 2020: 467.
Tremex longicollis: Miyatake, 1950: 38. Not Konow, 1896, in part.
Tremex fuscicornis: Miyatake, 1950: 38. Not Fabricius, 1787, in part. See Lee et al. (2019) for more references.
Diagnostic characters. Female (Fig. 1E). Length without ovipositor 21–32 mm. Head pale brown, with blackish area across ocellar area. Antenna wholly pale brown (Fig. 5F). Thorax black, with dorsal surface of pronotum, parascutal lobe and mesoscutellum pale brown; pronotum (Fig. 3J) usually without blackish longitudinal median line. Fore and mid legs brown, with part of coxa and often parts of trochanter and femur blackish to black and basal parts of tibia and tarsomere 1 creamy white; hind leg black, with tibia and tarsus dark brown (basal halves of tibia and tarsomere 1 creamy white). Forewing with distinct infuscation around cells R, 1R1, 2R1, basal and anterior parts of 3R1, 2Rs, 3M, 3Cu and area along veins M+Cu and Cu (Fig. 8E, F). Abdomen black, with following pale brown: Sometimes small anterior part of tergum 1, most of terga 2 and 3 (except for posterior margin), narrow anterior margins of terga 4–7, anterior 1/4 of tergum 8 (except for anterior lateral corner), posterior half of tergum 9, usually including entire precornal basin, and cornus. Antenna with 15–17 antennomeres. Pronotum (Fig. 3J) long, MPL 0.90–0.98 (average 0.93) times as long as OOCL. Hind tibia 0.91–1.03 (average 0.96) times as long as hind tarsomere 1; dorsal margin of hind tibia straight or very shallowly concave (Fig. 6E). Forewing 1.17–1.31 (average 1.23) times as long as ovipositor sheath. Abdominal tergum 8 0.97–1.25 (average 1.13) times as long as terga 5–7 combined; precornal basin long, 0.63–0.79 (average 0.71) times as long as wide, widest in median or posterior part (Fig. 11E); ovipositor sheath 2.51–2.70 (average 2.57) times as long as apical sheath.
Male. Length 16–24 mm. Head, antenna, thorax and legs black except as follows: one to three terminal antennomeres pale brown (Fig. 5M); fore leg with most of femur, tibia and tarsus pale brown; mid leg with large parts of femur, tibia and tarsus pale brown; hind leg with extreme base of tibia and tarsomeres 4 and 5 pale brown. Wings brownish infuscated, with distinct cloud around 2R1 (Fig. 9E); veins dark brown. Abdomen black with terga (2)3–7 and sterna 2–9 marked with pale brown (sometimes faded and inconspicuous). Antenna with 14–16 (usually 15) antennomeres. Pronotum (Fig. 4G) long, MPL 0.88–1.00 (average 0.96) times as long as OOCL. Hind tibia short, 1.10–1.24 (average 1.16) times as long as hind tarsomere 1.
Material examined. 9♀ 18³ (9♀ 17³ from Honshu and 1³ from Shikoku). See Appendix for collection data.
Distribution (Fig. 13). Japan (Honshu, Shikoku, Tsushima Island (Anonymous 2014)), Korea (Lee et al. 1998), China (Zhejiang (Xiao et al. 1992)).
Host plant. Fagaceae: Quercus serrata Murray (Nakahama et al. 2006).
Remarks. This species occurs in western part of Honshu, Shikoku and Tsushima Island in Japan with adult emergence in spring (Table 4). The female of T. contractus is characterized by the entirely pale brown antenna (Fig. 5F), the long pronotum (Fig. 3J), the hind tibia about as long as the hind tarsomere 1 and with the basal half creamy white and the apical half dark brown (Fig. 6E), the anterior margin of the forewing rather broadly infuscated with dark brown (Fig. 8E, F), the black abdominal tergum 8 (except for the anterior 1/4) and the short precornal basin (Figs 10J, 11E). The male is characterized by the entirely black head (Fig. 4G), the black antenna (a few terminal flagellomeres pale brown) with14–16 (usually 15) antennomeres (Fig. 5M), the long pronotum (Fig. 4G), the brownish infuscated wings with a distinct cloud around 2R1 (Fig. 9E), and the abdomen black with pale brown marks (tergum 8 entirely black) (Fig. 12 G).
In Japan, this species has been recorded from Osaka (Yoshida 2006; Nakahama et al. 2006; Naito 2020), Hyogo (Nakahama et al. 2006; Ushirokita et al. 2012), Okayama (Watanabe 1986), Hiroshima (Anonymous 2004), Ehime (Takeuchi 1955a) and Nagasaki (Tsushima Island, Anonymous 2014) prefectures. Here T. contractus is newly recorded from Kyoto and Nara prefectures (see Appendix for collection data).
description: Published as part of Shinohara, Akihiko, 2023, The woodwasp genus Tremex (Hymenoptera, Siricidae) of Japan, pp. 1-40 in Zootaxa 5239 (1) on pages 27-28, DOI: 10.11646/zootaxa.5239.1.1, http://zenodo.org/record/7621749