Taxonomy, annotated new records and a checklist of Mymaridae (Hymenoptera) of Finland, with description of a new species of Eustochus Author Triapitsyn, Serguei V. Entomology Research Museum, Department of Entomology, University of California, Riverside, California, 92521, USA; Author Koponen, Martti Tuoppitie Author Vikberg, Veli Liinalammintie 11 as. Author Várkonyi, Gergely Finnish Environment Institute SYKE, Biodiversity Centre, FI- 88900, Kuhmo, Finland; e-mail: gergely. varkonyi @ ymparisto. fi text Acta Entomologica Musei Nationalis Pragae 2020 2020-11-06 60 2 565 589 http://dx.doi.org/10.37520/aemnp.2020.39 journal article 10.37520/aemnp.2020.39 1804-6487 5177724 659934F0-6B73-4571-8ADA-5E14CD3669EC Erythmelus ( Erythmelus ) agilis (Enock, 1909) are accepted here and expanded as follows: clava of fe- Material examined. Ta : Janakkala, Kalpalinna (6757:8369), 7.vii.2017 , male antenna 1- (entire), 2- or 3-segmented. Caraphractus V. Vikberg ( 1 ♀ , VVCT ). Walker, 1846 was considered to be most closely related to Eustochus of which the former might be a derived offshoot; Distribution. Palaearctic ( Belgium , Bulgaria , Czech their only more or less significant difference was the claval Republic, Denmark , Finland , Germany , Greece , Italy , segmentation of the female antenna: entire in the former but Kyrgyzstan , Netherlands , North Macedonia , Norway , 2- or 3-segmented in the latter genus (Hඎൻൾ*© & Bൺඊඎൾ*©ඈ Russia , Serbia , Sweden , Switzerland , United Kingdom ) 2007). Both genera were known from eggs of Coleoptera and Nearctic ( Canada , USA ) Regions (T*©ංൺඉංඍඌඒඇ 2003b; (T*©ංൺඉංඍඌඒඇ 2012; P*©ං*öඈඉ & MඈǤඅൺඇ 2016) and are T*©ංൺඉංඍඌඒඇ et al. 2007; Sൺආκඈඏග et al. 2020). strictly Holarctic in distribution (Hඎൻൾ*© & Bൺඊඎൾ*©ඈ 2007). However, our discovery of two new species of Eustochus Eustochus Haliday, 1833 from Finland and Germany with an entire clava (see be- Caraphractus Walker, 1846 , syn. nov. , downgraded to a subgenus of low) shows that the variable segmentation of the clava in Eustochus is not a good genus-defining character, hence Remarks. The diagnoses of Eustochus Haliday, 1833 by the proposed synonymy of Caraphractus syn. nov. with Hඎൻൾ*© & Bൺඊඎൾ*©ඈ (2007) and P*©ං*öඈඉ & MඈǤඅൺඇ (2016)the earlier described Eustochus ; furthermore, the former is treated here as its subgenus, E. ( Caraphractus ) stat. revid. Caraphractus , with its sole valid member, the type species C. cinctus Walker, 1846 (= Eustochus ( Caraphractus ) cinctus (Walker, 1846) , comb. nov. ), is very likely essentially nothing more than just an aquatic species of Eustochus . However, while proposing this new generic synonymy, we also downgrade the taxonomic status of Caraphractus to that of a subgenus of Eustochus for the following reasons kindly provided by John T. Huber (personal communication): in female Caraphractus , mandible with 3 serrated teeth (2, not serrated teeth in most Eustochus s. str. except with 3 teeth in E. ( Eustochus ) koponeni ); petiole ventrally with strong reticulations (smooth in most Eustochus s. str. except in E. ( Eustochus ) koponeni ) and without a longitudinal suture (suture present at least partially in most Eustochus s. str. except in E. ( Eustochus ) koponeni ); first gastral tergum laterally with about 10 longish setae (such setae absent in Eustochus s. str. ); mps absent on funicle segments (present on several segments in Eustochus s. str. ). Also, male Caraphractus have 1 less antennal flagellar segment than male Eustochus s. str. , but these are known only for E. ( Eustochus ) atripennis (Curtis, 1832) .