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 Eustochus ( Eustochus ) koponeni Triapitsyn , sp. nov. ( Figs 8–9 ) Type material. Hඈඅඈඍඒඉൾ: ♀ ( FMNH ) on slide ( Fig. 8B ) labeled: 1. “ SUOMI KP:Vimpeli 7008:349 10.7.1985 M.Koponen leg.”; 2. “FMNH Mounted by V. V. Berezovskiy 2016 in Canada balsam”; 3. [magenta] “ Eustochus koponeni Triapitsyn HOLOTYPE ♀ ”; 4. “Det. by S. V. Triapitsyn 2016”. The type locality is in Southern Ostrobothnia ( Om ) region of Finland; the specimen was captured by sweeping in an open bog Hallaneva. The holotype was remounted from a point ( Fig. 8A ). Pൺ*©ൺඍඒඉൾ: ♀ ( NMEG ) on slide, labeled: “Germany, Sa-Anh, HZ, 4129/44 +4223/2 Blumentopfmoor N, Schierke, 640 m , Bodenfalle 1998-06- 24 F. Burger”.The locality is Blumentopfmoor (ca. 51°47’55’’N 10°39’44’’E , ca. 666 m ), a bog in Harz Mountains near the villages of Drei Annen Hohne and Schierke, Harz District, Saxony-Anhalt; the specimen was collected in a pitfall trap. Fig. 7. Eustochus ( Caraphractus ) cinctus (Walker, 1846) , female (holotype of Caraphractus flavicollis Hellén, 1974 ): A – habitus in dorsolateral view; B – habitus in dorsal view. Description. Female ( holotype ). Head black, rest of body ( Fig. 8A ) brown (mesosoma and petiole) to dark brown (gaster); appendages mostly brown to dark brown except 2 basal tarsomeres of hind leg light brown. Head ( Fig. 8C ) with reticulate sculpture; mandible 3-dentate. Antenna ( Fig. 9A ). Scape with a faint, inconspicuous sculpture, 4.6 times as long as wide (excluding a very short radicle); pedicel longer than any funicular segment; F2 and F3 the shortest and F4 the longest among funicular segments; mps on F4–F6 (apparently 2 on each); clava 2.3 times as long as wide, with 7 mps. Mesosoma ( Fig. 9B ) reticulate. Mesoscutum a little shorter than scutellum. Fore wing ( Fig. 9E ) almost 3.9 times as long as wide; venation extending to 0.46 of total wing length; longest marginal seta 0.74 times maximum width of wing; disc strongly infuscate (with brown) and densely setose. Hind wing ( Fig. 9E ) 16.5 times as long as wide; disc infuscate, longest marginal seta 3.6 times maximum width of wing. All coxae with reticulate sculpture, metafemur with a less conspicuous sculpture. Petiole ( Figs 9C, D ) reticulate, 1.5 times as long as wide, shorter than metacoxa. Ovipositor occupying 0.8 length of gaster ( Fig. 9D ), notably exserted beyond its apex (by 0.17 times own total length), 1.75 times length of mesotibia and 1.3 times length of metatibia. Measurements of the holotype (mm). Body (of the air-dried [straight after being collected in a net], pointmounted specimen prior to slide-mounting): 0.860; head (of the air-dried, point-mounted specimen prior to slide -mounting): 0.132; mesosoma 0.330; mesoscutum: 0.090; scutellum: 0.103; petiole 0.070; gaster 0.478; ovipositor 0.452.Antenna: radicle 0.018; rest of scape 0.140; pedicel 0.060; F1 0.027; F2 0.024; F3 0.024; F4 0.040; F5 0.035; F6 0.036; clava 0.173. Fore wing 0.935: 0.242; venation 0.430; longest marginal seta 0.180. Hind wing 0.695: 0.042; longest marginal seta 0.151. Mesotibia: 0.258; metatibia: 0.351. Fig. 8. Eustochus ( Eustochus ) koponeni Triapitsyn sp. nov. , female (holotype): A – habitus in dorsolateral view (prior to slide-mounting); B – slide; C – head in frontal view. Body length of the paratype (measured in ethanol) 1.073 mm . Male. Unknown. Diagnosis. The new taxon, which belongs to the nominotypical subgenus of Eustochus as defined here, differs from all other described Eustochus species keyed in Hඎൻൾ*© & Bൺඊඎൾ*©ඈ (2007) in having an entire clava of the female antenna. Female of E. koponeni differs from that of Eustochus ( Caraphractus ) cinctus (Walker, 1846) , comb. nov. , which also has an entire clava, in having F1–F3 distinctly shorter than F4–F6, each of which also with mps ( Fig. 9A ); in the latter, funicle segments are subequal in length and all lack mps (T*©ංൺඉංඍඌඒඇ 2012: 22,g fi. 1). Eustochus ( Eustochus ) koponeni is most similar to apparently an undescribed species from Finland , known from a single female ( Fig. 10A ) in VVCT ( Ta : Janakkala, Raimansuo (6760:3367), 27.vii.2017 , V. Vikberg), which was also collected at a bog. Its clava is also entire, but this Eustochus ( Eustochus ) sp. differs from that of E. koponeni in the following combination of features: antenna ( Fig. 11A ) with scape (minus radicle) 3.2 times as long as wide; fore wing ( Fig. 11E ) 3.3 times as long as wide and its longest marginal seta 0.5 times maximum wing width, hind wing ( Fig. 11E ) 17.8 times as long as wide; petiole ( Fig. 11B ) 1.8 times as long as wide; ovipositor short, occupying a little more than 0.5 length of gaster, and just barely exserted beyond apex of gaster ( Fig. 11D ), 1.5 times length of mesotibia and 0.95 times length of metatibia. It is not described here as a new taxon because its single available specimen has just one antenna ( Figs 10A , 11A ), and also because we do not know the full range of variability of these features in E. ( Eustochus ) koponeni . Body and head lengths of this Eustochus ( Eustochus ) sp., measured prior to slide-mounting, were 1.156 mm and 0.165 mm , respectively. Its body ( Fig. 10A ) and antenna are black, legs are dark brown to black except first 3 metatarsomeres are light brown, and fore wing ( Fig. 11E ) disc is notably infuscate. The antenna ( Fig. 11A ) has mps on F4–F6 and clava.Also illustrated here, to facilitate its recognition, are its head ( Fig. 10B ) and mesosoma ( Fig. 11C ). Fig. 9. Eustochus ( Eustochus ) koponeni Triapitsyn sp. nov. , female (holotype): A – antenna (radicle attached to the head in Fig. 5C); B – mesosoma; C – petiole; D – metasoma; E – fore and hind wings. Fig. 10. Eustochus ( Eustochus ) sp. near koponeni , female (Raimansuo, Janakkala, Tavastia Proper, Finland):A – habitus (lateral view); B – head (frontal view). Etymology. The new species is named after its first collector (of the holotype ). Distribution. Palaearctic Region ( Finland , Germany ) (this paper).