Megastylus (Dicolus) pectoralis
Creators: name: Watanabe, Kyohei
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Ichneumonidae
Megastylus
Megastylus pectoralis

description: Megastylus (Dicolus) pectoralis (Förster, 1871)
[New SJN: Suneboso-ashinaga-hae-himebachi]
(Figs. 14A–D, 23K)
Dicolus pectoralis Förster, 1871: 97.
Dicolus subtiliventris Förster, 1871: 97.
Diagnosis. Hind tibia swollen in basal 2/3 and distinctly narrowed in apical 1/3 (Fig. 23K). Propodeum with a distinct transverse depression anterior 0.25–0.28, without lateromedian longitudinal carina and anterior transverse carina. T I 3.8–4.0 times as long as maximum width. Coxae yellow to brown, usually apex of hind coxa weakly darkened (Fig. 14A). In female: clypeus, mesopleuron, and T III reddish yellow to reddish brown (Figs. 14B, C). In male: frontal orbit, face, clypeus (Fig. 14 D), mesopleuron, and T III yellow to reddish brown; pronotum and mesoscutum sometimes with yellow to brown marking. Fore wing length 3.3–5.5 mm.
Material examined. JAPAN: NARO, 1 F & 1 M, Hokkaido, Mt. Daisetsu, Asahidake, 10. VII. 1970, H. Hasegawa leg.; EUM, F, Hokkaido. Sapporo City, Hitsujigaoka, 2–9. VII. 2003, K. Konishi leg. (MsT); EUM, F, ditto, 19–26. XI. 2003; NARO, 2 M, Hokkaido, Sapporo City, Jozankei, 29. VIII. – 12. IX. 1989, K. Maeto & M. Sharkey leg. (MsT); NARO, 2 F, ditto, 12–21. IX. 1989; NARO, 3 M, ditto, 21–28. IX. 1989; NARO, 2 M, Hokkaido, Kumaishi, Kenichi-gawa, Iwafuchi-zawa, 1–11. X. 1995, Y. Ito & T. Ito leg. (MsT); NARO, 1 F & 1 M, ditto, 10–20. X. 1995; NARO, F, Hokkaido, Sapporo City, Misumai, Kannon-zawa, 3–15. IX. 1992, N. Kuhara leg. (MsT); NARO, M, 4–17. VII. 1993; NARO, F, Yamagata Pref., Oguni Town, Chojagahara, 7. VI. 1980, H. Takemoto leg.; NARO, M, Fukushima Pref., Hinoemata, 1–2. VII. 1989, K. Konishi leg.; NARO, M, Tochigi Pref., Yaita, 22. VIII. – 8. IX. 1989, K. Konishi leg. (MsT); KPM-NK 89792, M, Kanagawa Pref., Atsugi City, Nakaogino, 26. IV. 2008, M. Gunji leg.; KPM-NK 89793, 89794, 2 F, Yamanashi Pref., Koushu City, Yanagisawatoge, 5. VIII. 2008, K. Watanabe leg.; KPM-NK 89795, M, ditto, M. Gunji leg.; KPM-NK 89796, Yamanashi Pref., Koushu City, Hikawa, 15. VII. 2010, K. Watanabe leg.; NARO, 4 M, Nagano Pref., Shimashima-dani, 27. VII. 1980, K. Maeto leg.; NARO, F, ditto, H. Takemoto leg,; NARO, ditto, 28. VII. 1980; NARO, 1 F & 2 M, ditto, K. Maeto leg.; NARO, F, Nagano Pref., Norikurakogen, 13. X. 1982, K. Konishi leg.; KPM-NK 89797, F, Nagano Pref., Ueda City, Sugadaira-kogen, Tsukuba Univ., 8. VIII. – 3. IX. 2014, S. Shimizu leg. (MsT); NARO, 4 M, Niigata Pref., Kurokawa Vil., Tainai, 3–4. VI. 1980, K. Maeto leg.; NARO, 3 M, ditto, 8. VI. 1980; KPM-NK 80915, F, Niigata Pref., Nagaoka City, Suyoshi Town, Mt. Nokogiri-yama, 21. VII. – 21. VIII. 2014, S. Shimizu & R. Shimizu leg. (MsT); KPM-NK 89798, F, Shizuoka Pref., Fujinomiya City, Nishiusuzuka, 15. X. 2006, H. Katahira leg.; KPM-NK 89799, 89800, 2 M, Shizuoka Pref., Kawanehoncho Town, Yamainudan, 14. VI. 2008, K. Watanabe leg.; KPM-NK 89801, F, Toyama Pref., Toyama City, Arimine, Jyuroudani, 8–15. IX. 2009, M. Watanabe et al. leg. (MsT); NARO, F, Tokushima Pref., Ichiu Vil., Mt. Tsurugi-san, 16. X. 1980, T. Goto leg.; KPM-NK 89802, M, Saga Pref., Tara Town, Taradake, 20. V. 2001, T. Yamauchi leg.; NARO, F, Oita Pref., Mts. Kuju, Daisenrido, 18. VII. 1978, K. Setoya leg. GERMANY: ZSM, F (det. Rossem), Obbayern, Umg., Gauting, 3. VI. 1912, Haeselbarth leg.
Distribution. Japan (Hokkaido, Honshu, Shikoku, and Kyushu); widely distributed in Holarctic and Neotropical regions (Yu et al., 2016).
Remarks. This is the first record of this species from Japan.
description: Published as part of Watanabe, Kyohei, 2023, Taxonomic and Zoogeographic Notes on Japanese Orthocentrinae (Hymenoptera, Ichneumonidae), with Descriptions of Four New Species, pp. 7-44 in Bulletin of the Kanagawa Prefectural Museum (Natural Science) 52 on pages 28-29, DOI: 10.5281/zenodo.11283244