title: Descriptions of unknown sexes, new geographical records, and host associations for two South American species of Megachile (Hymenoptera: Megachilidae).
abstract: The cosmopolitan genus Megachile include many species described on the basis of only one sex. Sexual dimorphism is very pronounced in these taxa and therefore sexes are often difficult to associate, thus making species identification nearly impossible. The females of M. (Chrysosarus) concava and M. (Pseudocentron) variplantis are described and illustrated. Additional geographical and host records are provided as well as comments on their diagnostic features and identification based on existing keys.
authors.affiliation: División Entomología, Museo de La Plata, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Paseo del Bosque s/n, B1900DNG La Plata, Argentina.; Email: sdurante@fcnym.unlp.edu.ar.
authors.forename: Silvana
authors.initials: S
authors.lastname: Durante
authors.affiliation: Cátedra de Botánica General, Facultad de Agronomía. Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE, Buenos Aires, Argentina.; Email: torretta@agro.uba.ar.
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Torretta
authors.affiliation: División Entomología, Museo de La Plata, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Paseo del Bosque s/n, B1900DNG La Plata, Argentina.; Email: sdurante@fcnym.unlp.edu.ar.
authors.forename: Maria Guadalupe
authors.initials: MG
authors.lastname: Colombo
mesh_terms: D063147:Animal Distribution; D000825:Animal Structures / Q000033:anatomy & histology; D000818:Animals; D001516:Bees / Q000033:anatomy & histology / Q000145:classification*; D017753:Ecosystem; D005260:Female; D008297:Male