Megastylus (Dicolus) impressor Schiodte 1838
Creators: name: Watanabe, Kyohei
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Ichneumonidae
Megastylus
Megastylus impressor

description: Megastylus (Dicolus) impressor Schiødte, 1838
[New SJN: Futahida-ashinaga-hae-himebachi]
(Figs. 13A–C, 23F, I, J)
Megastylus impressor Schiødte, 1838: 139.
Dicolus insectator Förster, 1871: 97.
Diagnosis. Inner eye orbit slightly converged ventrally (Fig. 13B). FL I 9.0–11.0 (female) or 12.0 (male) times as long as maximum depth in lateral view. Fore TS I shorter than half length of fore tibia (Fig. 23I). Hind tibia not distinctly narrowed in apical 1/3 (usually slightly narrowed) (Fig. 23J). Propodeum with a distinct transverse depression anterior 0.25–0.28, with both anterior and posterior transverse carinae (Fig. 23F). T I and T II without longitudinal striae. Fore wing length 3.6–5.3 mm. In female: fore TS I 0.33–0.43 length of fore tibia; antennal cleaner of fore TS I not causing conspicuous outcurving of base of TS I. In male: face darkened, except for a narrow yellow area below antennal sockets; pronotum yellow ventrally; mesoscutum darkened; mesopleuron and scutellum reddish brown; hind femur 7.0–8.6 times as long as width in lateral view; T I 2.8–3.3 times as long as maximum width.
Material examined. JAPAN: NARO, M, Hokkaido, Kumaishi, Kenichi-gawa, Iwafuchi-zawa, 21– 29. IX. 1995, Y. Ito & T. Ito leg. (MsT); EUM, F, Hokkaido, Bifue, Kusabue-rindo, 17. VIII. – 1. IX. 2012, N. Kuhara leg. (MsT); KPM-NK 89769, F, Niigata Pref., Nagaoka City, Suyoshi Town, Mt. Nokogiri-yama, 21. VII. – 21. VIII. 2014, S. Shimizu & R. Shimizu leg. (MsT); KPM-NK 89769, F, ditto, 21. VIII. – 22. IX. 2014; KPM-NK 89770, F, Toyama Pref., Toyama City, Arimine, Inonedani, 7–14. VII. 2009, M. Watanabe leg. (MsT); KPM-NK 89771, F, ditto, 14–21. VII. 2009; KPM-NK 89772, F, ditto, 21–28. VII. 2009; KPM-NK 89773, F, Toyama Pref., Toyama City, Arimine, Jyurodani, 16–25. VIII. 2009, M. Watanabe leg. (MsT); KPM-NK 89774, F, Toyama Pref., Toyama City, Kamegai, 1–8. IX. 2009, M. Watanabe leg. (MsT); KPM-NK 89775, F, ditto, 15–26. IX. 2009; KPM-NK 89776, F, Toyama Pref., Toga Vil., Kamimomose, 18–25. Aug. 2009, M. Watanabe leg. (MsT); KPM-NK 89777, 89778, 2 F, ditto, 1–8. IX. 2009; KPM-NK 89779, 89780, 2 F, ditto, 15–29. IX. 2009; KPM-NK 89782, M, Tochigi Pref., Nasushiobara City, Shiobara, Oonuma, 6–15. VI. 2008, T. Matsumura leg. (MsT); KPM-NK 80781, M, Kanagawa Pref., Yamakita Town, Minasegawa, 5. V. 2008, S. Yoshizawa leg.; KPM-NK 89783, M, Yamanashi Pref., Koushu City, Sagashio, 6. VIII. 2008, K. Watanabe leg.; KPM-NK 89785, M, Nagano Pref., Tateshina Town, Ashidahakkano, Mt. Tateshina, 26. VIII. 2011, S. Fujie leg.; KPM-NK 89784, M, Shizuoka Pref., Kawanehoncho, Yamainudan, 14. VI. 2008, K. Watanabe leg.; OMNH, F, Ishikawa Pref., Kaga City, Mt. Kariyasu-yama, 28. VI. – 19. VII. 2002, K. Esaki leg. (MsT); OMNH, M, Kyoto Pref., Miyadu City, Kamiseya, Seyakogen, 10. X. 2015, S. Fujie leg.; NIAES, 2 F & 3 M, Fukuoka Pref., Mt. Hiko, 2–3. XI. 1979, H. Takemoto leg. GERMANY: F (det. Rossem), D, BY, Starnberg, Kerschlach, 27. VII. 1927, Haeselb. leg.
RUSSIA: ZISP, M (det. Rossem), Kobralovo-Semrino, 29. VI. 1980, D. R. Kasparyan leg.
Distribution. Japan (Hokkaido, Honshu, and Kyushu); widely distributed in Holarctic region (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 27-28, DOI: 10.5281/zenodo.11283244