A key to the species of Nanoplebeia, with descriptions of four new species (Hymenoptera: Apidae) Author Engel, Michael S. Division of Entomology, Natural History Museum, and Department of Ecology & Evolutionary Biology, 1501 Crestline Drive - Suite 140, University of Kansas, Lawrence, Kansas 66045 - 4415, USA (msengel @ ku. edu). & Division of Invertebrate Zoölogy, American Museum of Natural History, Central Park West at 79 Street, New York, New York 10024 - 5192, USA. text Journal of Melitology 2021 2021-08-27 2021 106 1 14 http://dx.doi.org/10.17161/jom.i106.15735 journal article 10.17161/jom.i106.15735 2325-4467 8057545 urn:lsid:zoobank.org:pub:3A15339D-6C13-4FCD-B847-71B747F5EBF9 Simplified Key to Species of Nanoplebeia (worker caste) 1. Body largely black to light brown, sometimes with extensive yellow or yellowish orange on pleura, legs, and metasoma ( e.g ., Figs. 1–3 , 11, 13–17 ) .................. 2 —. Body entirely yellowish orange to orange ( e.g ., Figs. 5 , 12 ) .................................... ...................................................................................................... P . ( N .) franki (Friese) 2(1). Mesepisternum, metepisternum, and propodeum brown to black ( e.g ., Figs. 2, 3 ); metasoma brown to black; legs variable but never wholly yellowish orange to orange ...................................................................................................................... 3 —. Mesepisternum, metepisternum, and propodeal lateral surface with extensive yellow to yellowish-orange ( Fig. 1 ); legs and metasoma wholly yellowish orange to orange ( Fig. 1 ) ........................................................ P . ( N .) margaritae Moure 3(2). Mesoscutellum with whitish to yellowish maculation restricted to medioapical margin ( Figs. 13–15, 17 ); basal area of propodeum microreticulate, sometimes faintly so ...................................................................................................................... 4 —. Mesoscutellum with maculation extending along entire margin, meeting axillae laterally ( Fig. 16 ); basal area of propodeum smooth ......... P . ( N .) pleres , n. sp. 4(3). Yellow maculation in paraocular area strong and distinct, clearly extending upward along inner orbit above tangent of antennal toruli upper margins ( Figs. 6, 7 , 10 ) ............................................................................................................................. 5 —. Yellow maculation in paraocular area fainter, disappearing at tangent of antennal toruli upper margins ( Fig. 8 ) ............................................ P . ( N .) asthenes , n. sp. 5(4). Punctures on frons comparatively coarse ( Figs. 6 , 10 ); mesosomal maculation white to pale yellow ( Figs. 13 , 17 ); mesosomal punctures more distinct ( Figs. 13 , 17 ); fine, short, mesoscutal setae largely 0.75–1.0× width of mesoscutal lateral yellow stripe ( Figs. 13 , 17 ) ......................................................................................... 6 —. Punctures on frons comparatively fine ( Fig. 7 ); mesosomal maculation typically lemon yellow ( Fig. 14 ); mesoscutal punctures more indistinct ( Fig. 14 ); fine, short, mesoscutal setae largely less than half width of mesoscutal lateral yellow stripe ( Fig. 14 ) ..................................................................... P . ( N .) minima (Gribodo) 6(5). Metabasitarsal superior distal angle broadly rounded; metatibial length 2.4– 2.5× width .................................................................................... P . ( N .) orphne , n. sp. —. Metabasitarsal superior distal angle projecting and acutely rounded; metatibial length 2.3× width ...................................................................... P . ( N .) chondra , n. sp.