A new bee genus from the pampas of eastern Argentina, with appended notes on the classification of “ paracolletines ” (Hymenoptera: Colletidae) 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. Author Gonzalez, Victor H. Undergraduate Biology, and Department of Ecology & Evolutionary Biology, 1200 Sunnyside Avenue, University of Kansas, Lawrence, Kansas 66045, USA (vhgonza @ ku. edu). text Journal of Melittology 2022 2022-01-24 2022 109 1 39 http://dx.doi.org/10.17161/jom.i109.16424 journal article 10.17161/jom.i109.16424 2325-4467 13146121 6C96BAB7-7AF6-4B8B-A2EF-08BD9F3A1344 Machaerocolletes Engel , new genus ZooBank: urn:lsid:zoobank.org:act: 321B5AFE-229D-457C-8469-2F9341FB8CCD TYPE SPECIES : Leioproctus glendae Batley in Batley & Popic , 2016. DIAGNOSIS: This genus resembles Colletellus Michener but differs most notably in the peculiarly modified mandible, which is broadened in the basal two thirds and then abruptly and greatly tapered to a long, simple, apical tooth; the elongate and flatened female probasitarsus with long, erect, thick, simple setae; the protibial calcar thickened and lacking a malus; and the bifid apex to the male sternum VIII. ETYMOLOGY: The new generic name is taken from Ancient Greek mákhaira ( μάΧαιρα , meaning, “dagger” or “dirk”), in reference to the mandibular form, and kollitís ( κολλητής , meaning, “gluer” or “one who glues”). The gender of the name is masculine.