Megastylus (Dicolus) pectoralis ( Förster, 1871 )

Watanabe, Kyohei, 2023, Taxonomic and Zoogeographic Notes on Japanese Orthocentrinae (Hymenoptera, Ichneumonidae), with Descriptions of Four New Species, Bulletin of the Kanagawa Prefectural Museum (Natural Science) 52, pp. 7-44 : 28-29

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.