Taxonomic and Zoogeographic Study of the Japanese Phygadeuontinae (Hymenoptera, Ichneumonidae), with Descriptions of 17 New Species Author Watanabe, Kyohei Kanagawa Prefectural Museum of Natural History, 499 Iryuda, Odawara, Kanagawa 250 – 0031, Japan watanabe-k@nh‛kanagawa-museum‛jp text Bulletin of the Kanagawa Prefectural Museum (Natural Science) 2021 2021-03-30 50 55 136 https://doi.org/10.32225/bkpmnh.2021.50_55 journal article 300009 10.32225/bkpmnh.2021.50_55 70224806-ca38-47ca-bd8a-63da3ac532f9 2189-6720 12774639 DD695C62-DC2F-4D32-8D33-52648E28661D Genus Acrolyta Förster, 1869 Acrolyta Förster, 1869: 174 . Type : Acrolyta empretiae Ashmead, 1896 (= Ischnoceros nigricapitatus Cook & Davis, 1891 ). Designated by Viereck (1914) . Rhadinocera Förster, 1869: 177 . Type : Hemiteles ( Rhadinocera ) algonquinus Viereck, 1917 (= Ischnoceros nigricapitatus Cook & Davis, 1891 ). Included by Viereck (1922) . Mosia Seyrig, 1952: 69 . Type : Mosia crassicornis Seyrig, 1952 . Original designation. Parhemiteles Seyrig, 1952: 82 . Type : Parhemiteles flaviger Seyrig, 1952 . Original designation. Five species, Acr. albiscapus (Ashmead, 1906) , Acr. aporiae ( Okamoto, 1923 ) , Acr. discrepa Momoi, 1970 , Acr. excisa Momoi, 1970 , and Acr. spola Momoi, 1970 , have been recorded from Japan . Among them, Acr. albiscapus is treated as status ( Yu et al ., 2016 ). I found at least 13 species of this genus from Japan . Two of them, Acr. flavicoxis Sheng & Sun, 2014 and Acr. rufocincta ( Gravenhorst, 1829 ) , are newly recorded from Japan here. In addition, one new species and at least five unidentified species are also recognized. In this study, I record five described species including the newly recorded species with some distributional data and describe a new species, Acr. japonica sp. nov. below. Schwarz & Shaw (2000) revised the generic concepts of this genus and of Eudelus Förster, 1869 . I re-examined the generic position of all Japanese species based on it and concluded their character statuses are accorded with the Acrolyta . No identification key to Japanese species has been provided except for the key to the Ryukyu species according to Momoi (1970) , thus I provide a preliminary key to the Japanese species below. Preliminary key to Japanese species of the genus Acrolyta ( ♀ ) (female of Acr. albiscapus is unknown) 1. Metasomal tergites at least partly (usually T II and T III entirely) reddish brown to reddish yellow ( Figs 5A, C ). Clypeus with ( Fig. 62G ) or without a pair of distinct teeth anteromedially. .............................................................................. 2 -. Metasomal tergites black except that the posterior margins usually tinged with reddish brown to reddish yellow (e.g., Figs 2C , 3C , 6C ). Clypeus without a pair of distinct teeth anteromedially ( Fig. 62F ). .............................................................................. 3 2. Clypeus with a pair of distinct teeth anteromedially ( Fig. 62G ). T II striated and the interspace of striae smooth. .................................. Acr. rufocincta ( Gravenhorst, 1829 ) -. Clypeus without a pair of distinct teeth anteromedially. T II reticulate rugose except for smooth posterior margin. .............................................................................. Acr . sp. A 3. Anterior margin of clypeus distinctly entirely rounded. .............................................................................. 4 -. Median part of anterior margin of clypeus truncate, subtruncate ( Fig. 62F ) or slightly concave. .............................................................................. 5 4. Posterior half of T II and T III largely smooth, without striae ( Fig. 1C ). Face matt. Hind coxa blackish brown ( Fig. 1A ). ........................................... Acr. aporiae ( Okamoto, 1923 ) -. Above combination of character states lacking. ....................... Acr . spp. (including at least 2 spp.) 5. Hind coxa black. Hind femur usually darkened basally. ....................... Acr . spp. (including at least 2 spp.) -. Hind coxa yellowish brown or reddish brown (e.g., Figs 2A , 4A ), or if largely tinged with blackish brown, clypeus with dense setae and hind femur nearly entirely yellow. .............................................................................. 6 6. T II without striae. T III covered with sparse and fine punctures, without dense punctures and striae. Mesoscutum largely polished. Median part of flagellum slightly wider than other parts, its maximum width less than 2.0 times as long as maximum depth of FL I in lateral view. Ovipositor sheath 0.9 times as long as hind tibia. ................................................ Acr. discrepa Momoi, 1970 -. T II covered with dense punctures and/or striae (e.g., Figs 2C , 3E , 4C , 6C ). T III sometimes covered with dense punctures and/or striae. Mesoscutum largely matt (e.g., Figs 2C , 4C , 6C ). Other character states various. .............................................................................. 7 7. T II and T III covered with longitudinal striae except for smooth areas ( Fig. 4C ). .......................................................... Acr. japonica sp. nov. -. At least T III without longitudinal striae. .............................................................................. 8 8. T II and T III polished and punctate, with some longitudinal striae on basal part of T II ( Fig. 3E ). Antenna robust and strongly widened except for basal part ( Figs 3A, C ). FL III 2.0 times as long as maximum depth in lateral view ( Fig. 62O ). .................................. Acr. flavicoxis Sheng & Sun, 2014 -. T II and T III covered with dense punctures or minute irregular rugae except for smooth areas, without longitudinal striae ( Figs 2C , 6C ). Antenna slender. FL III longer than 4.0 times as long as maximum depth in lateral view. ........................................................................ 9 9. Propodeum moderately long, evenly convexly descending, its dorsal face much longer than the hind face ( Fig. 2A ). Pterostigma light brown ( Fig. 2A ). ............................................... Acr. excisa Momoi, 1970 -. Propodeum short, abruptly, strongly declivous behind, its dorsal face much shorter than the hind face ( Fig. 6A ). Pterostigma dark brown ( Figs 6A, D ). ................................................. Acr. spola Momoi, 1970