Redescription of the genus Megastilicus Casey (Staphylinidae, Paederinae) with the description of a new species Author Żyła, Dagmara 0A7FEB0F-308C-4FDF-AD0D-8074BC69F0B3 Department of Invertebrate Zoology and Parasitology, University of Gdańsk, 80 - 308, Gdańsk, Poland. & Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA. & Museum and Institute of Zoology, Polish Academy of Sciences, Wilcza 64, 00 - 679, Warszawa, Poland. zyladagmara@gmail.com Author Koszela, Katarzyna 06C16202-4569-4156-9FB1-EA4DEE14AE88 Museum and Institute of Zoology, Polish Academy of Sciences, Wilcza 64, 00 - 679, Warszawa, Poland. kat.koszela@gmail.com text European Journal of Taxonomy 2021 2021-11-22 778 138 147 journal article 3366 10.5852/ejt.2021.778.1575 e9b6381f-da1b-47c3-b232-596c9c9af970 2118-9773 5718409 33DA5677-6AC0-4A27-A9B8-763FCCE4C416 Megastilicus formicarius Casey, 1889 Fig. 1 Type material Lectotype (here designated) USA • ♂ ; “Drac. Mass. / Type USNM 38356 / Megastilus formicarius Csy ”; NMNH . Paralectotypes USA • 1 spec. ; “Drac. Mass. / Casey bequest 1925 / formicarius-5 PARATYPE USNM 38356 ”; NMNH • 1 spec. ; “Casey bequest 1925 / formicarius-2 PARATYPE USNM 38356 ”; NMNH • 1 spec. with ant; “Casey bequest 1925 / formicarius-3 PARATYPE USNM 38356 ”; NMNH • 1 ♂ ; “Mass / Casey bequest 1925 / formicarius-6 PARATYPE USNM 38356 ”; NMNH . Additional studied material USA • 1 spec. ; “Pen Mar Pa”; NMNH • 1 spec. ; “ Harrisonville Mo. / Aug 2015 ”; NMNH • 1 spec. ; “ Cumberland Co. / Maine 1916”; NMNH • 1 spec. ; “ Newark NJ”; NMNH • 1 spec. ; “ Linell? Coll Chittenden ”; NMNH • 1 ♂ ; “ CypMills Tex / Coll Chittenden ”; NMNH • 1 spec. ; “ Sherborn , Massachusetts / IV-5 ’-25 / C.A. Frost /John George Gehring collection”; MCZ • 1 spec. [with Formica exsectoides ]; “Wickham collection 1933 / Iowa City / Wickham IV-24-98 ”; MCZ • 2 specs ; “ Natick / V-12-12 / Mass”; MCZ • 9 specs ; “ Drac. Mass / 4/4/-86 ”; MCZ • 1 spec. [with Formica exsectoides ]; “ Newfoundl’d , N.J. / X.17.1913 / C.A. Frost / C.A. Frost Collection 1962”; MCZ • 1 spec. ; “ Chocorua N.H. / 5-2-06 / F.C. Bowditch Collection ”; MCZ • 1 spec. ; “ Palos Park / Ill. / 4.14.34 / c. Seevers”; AMNH • 1 spec. ; “ Natik Mass. Frost. 12.5 / Massachusetts / N.am / Mus 8 crm”; AMNH • 1 spec. ; “ Crawfordsville Ind. 4.XII.50 ”; AMNH . Diagnosis Head longer than wide.Antennomere 4 elongate. Teeth on labrum blunt. Eyes smaller than in M . iowaensis sp. nov. , ca ⅙ of head length. Median emargination of posterior margin of sternum VIII deeper and broader than in M. iowaensis sp. nov. Redescription BODY. Colour of specimens from pale brown/sandy to brown ( Fig. 1A–B ). Head and tip of abdomen darker. Body length from tip of head to tip of abdomen 5.5–6.0. HEAD. Width 1.0–1.1, length 1.0–1.5. Antennomere 1 elongate, widest at tip; antennomeres 2 and 3 elongate; antennomere 4 weakly elongate; antennomeres 5 to 10 gradually becoming strongly transverse; antennomere 11 elongate, 1.5 × as long as antennomere 10. Antennomeres 1 and 2 sparsely pubescent; antennomeres 3 and 4 more densely pubescent, 5 to 11 densely covered with tomentose pubescence. Maxillary palpomere 2 short and slender, with only few setae, maxillary palpomere 3 slightly expanded towards apex with denser setation, maxillary palpomere 4 glossy. Eyes about ⅙ of head length, shifted anteriorly, ¼ to ⅕ of temple length. THORAX. Pronotum width 0.9–1.0, length 1.0–1.1. Elytra width 1.4–1.5, length 1.3–1.4. LEGS. Two long setae on outer margin of metacoxa. Seta closer to abdomen longer and thicker than seta more distant from abdomen. ABDOMEN. Sternum VII with apical margin straight. Tergum VIII with rounded posterior margin. Male with sternum VIII with moderately deep and broad median emargination of posterior margin; depth of emargination of ca ⅕ of sternum length; sides of emargination rounded ( Fig. 1C ); surface right anterior to emargination without setae, while margins with dense setation. AEDEAGUS. With ventral process in parameral view narrower in middle; lateral plates of internal sac fused to sides of median lobe and indistinctive ( Fig. 1D–E ). Occurrence The species has previously been recorded from the Canadian provinces of Manitoba, Newfoundland and Labrador, and Ontario and the following US states: Illinois , Indiana , Iowa , Massachusetts , New Jersey and Ohio (A. Newton, unpublished database). New state records include: Missouri , New Hampshire , Pennsylvania and Texas .