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 Sarocolletidion Engel , new genus ZooBank: urn:lsid:zoobank.org:act: 1CEC1011-36C6-4292-9F12-0691CEA667B6 TYPE SPECIES : Leioproctus ( Sarocolletes ) duplex Michener, 1989 . DIAGNOSIS: This genus is clearly related to Sarocolletes Michener and could perhaps be easily classified as a thid subgenus of Holmbergeria Jörgensen . It differs from Sarocolletes most obviously by the presence of only two submarginal cells (rather than three in Sarocolletes ) and the generally smaller size (total lengths of 7–8 mm versus 9–11.5 mm in Sarocolletes ). In addition, the basal area of the propodeum is shining and largely smooth, aside from some fine transverse ridges basally ( versus mate and imbricate in Sarocolletes ), and the labrum is convex apically (rather than broadly concave in Sarocolletes ). In most other features, the genus agrees with Michener’s (1989) account of Sarocolletes . ETYMOLOGY: The new generic name is a combination of Sarocolletes and the Ancient Greek diminutive suffix – ídion (– ῐ́δῐον ). The gender of the name is neuter.