Redefinition of the sexstrigatus group of Lasioglossum (Hemihalictus) Cockerell, 1897 (Hymenoptera, Apoidea, Halictidae), with a revision of Japanese species Author Murao, Ryuki 7E665839-6675-4365-A7EA-169D4E4DA008 Regional Environmental Planning Co., Ltd, 1 - 10 - 12, Muromi, Sawara-ku, Fukuoka, 814 – 0015 Japan. r.murao@mbr.nifty.com text European Journal of Taxonomy 2021 2021-08-18 763 1 74 http://dx.doi.org/10.5852/ejt.2021.763.1463 journal article 4854 10.5852/ejt.2021.763.1463 31f73be9-4a90-4c0a-937e-784437eff4bd 2118-9773 5235968 9823AAD7-1113-434B-9882-1CF885DE7CED Lasioglossum ( Hemihalictus ) Cockerell, 1897 Hemihalictus Cockerell, 1897: 288 (also published as new by Cockerell 1898 ) ( type species: Panurgus lustrans Cockerell, 1897 , by original designation). Sudila Cameron, 1898: 52 ( type species: Sudila bidentata Cameron, 1898 , by designation of Sandhouse 1943 ). Prosopalictus Strand, 1913: 26 ( type species: Prosopalictus micans Strand, 1913 , by original designation and monotypy). Ceylonicola Friese, 1918: 501 ( type species: Ceylonicola atra Friese, 1918 = Sudila bidentata Cameron, 1898 , by designation of Sandhouse 1943 ). Halictus ( Microhalictus ) Warncke, 1975: 85 ( type species: Melitta minutissima Kirby, 1802 , by original designation). Halictus ( Puncthalictus ) Warncke, 1975: 87 ( type species: Hylaeus punctatissimus Schenck, 1853 , by original designation). Halictus ( Rostrohalictus ) Warncke, 1975: 88 ( type species: Halictus longirostris Morawitz, 1876 , by original designation and monotypy). Halictus ( Marghalictus ) Warncke, 1975: 95 ( type species: Hylaeus marginellus Schenck, 1853 , by original designation). Lasioglossum ( Sellalictus ) Pauly, 1980: 120 ( type species: Halictus latesellatus Cockerell, 1937 , by original designation). Halictus ( Pauphalictus ) Warncke, 1981: 87 ( type species: Halictus pauperatus Brullé, 1832 , by original designation). Lasioglossum ( Mediocralictus ) Pauly, 1984: 143 ( type species: Halictus mediocris Benoist, 1962 , by original designation) . Evylaeus ( Limbevylaeus ) Pesenko, 2007a: 20 ( type species: Halictus limbellus Morawitz, 1876 , by original designation). Evylaeus ( Crassevylaeus ) Pesenko, 2007a: 20 ( type species: Halictus crassepunctatus Blüthgen, 1923 , by original designation and monotypy). Evylaeus ( Laevinodilaeus ) Pesenko, 2007a: 20 ( type species: Halictus laevinodis Morawitz, 1876 , by original designation and monotype). Evylaeus ( Pallidevylaeus ) Pesenko, 2007a: 23 ( type species: Nomioides pallida Radoszkowski, 1888 , by original designation and monotypy). Evylaeus ( Nitidiusculaeus ) Pesenko, 2007a: 24 ( type species: Melitta nitidiuscula Kirby, 1802 , by original designation). Evylaeus ( Truncevylaeus ) Pesenko, 2007a: 24 ( type species: Halictus truncaticollis Morawitz, 1877 , by original designation). Diagnosis In eastern Asia, the species of Hemihalictus series are classified into four subgenera ( Acanthalictus , Dialictus , Hemihalictus , and Sphecodogastra ). The subgenus Hemihalictus is separated from the other three subgenera by the following key: 1. Lower margin of male clypeus deflected forward; female labrum without basal elevation; basal elevation of male labrum stongly swollen, with longitudinal furrow; female mandible with two preapical teeth; male S2 gently swollen on apical part; male S6 expanded apically ( Murao et al . 2014 : figs 5–8, 15, 20) ........................................................................ Acanthalictus Cockerell, 1924 – Male clypeus normal, not deflected; female labrum with basal elevation (as in Fig. 4D ); male labrum without basal elevation or with low basal elevation; female mandible with a preapical tooth; male S2 flat; male S6 straight apically ............................................................................................................ 2 2. Head and mesosoma with brilliant or dull green-metallic luster in both sexes (mesepisternum with shallow PP or reticulate PP in both sexes, see Murao et al . 2015b : figs 1e, 6e, 20e).......................... ................................................................................................................... Dialictus Robertson, 1902 – Body generally black ......................................................................................................................... 3 3. Posterior surface of propodeum generally with complete lateral carina ( Murao 2017a : fig. 3b); mesepisternum with coarse reticulate-rugulae over entire surface ( Murao 2017a : fig. 2c)................. ......................................................................................................... Sphecodogastra Ashmead, 1899 – Posterior surface of propodeum with incomplete lateral carina not reaching metapostnotum ( Murao 2017a : fig. 3c); mesepisternum with shallow or reticulate PP ( Fig. 2E ; Murao 2017b : fig. 1d) ......... ............................................................................................................. Hemihalictus Cockerell, 1897 Three species, L . ( Sphecodogastra ) boreale Svensson, Ebmer & Sakagami, 1977 , L . ( S .) solisortus Ebmer & Maeta, 1994 , and L . ( S .) subtropicum Sakagami, Miyanaga & Maeta, 1994, from Japan are similar to L . ( Hemihalictus ) by having the posterior surface of the propodeum with an incomplete lateral carina (sometimes as variation) ( Murao & Tadauchi 2007 ). However, these species can be separated from L . ( Hemihalictus ) by the mesepisternum with coarse reticulate-rugulae.