Megachilinae, Latreille, 1802

Gonzalez, Victor H., Gustafson, Grey T. & Engel, Michael S., 2019, Morphological phylogeny of Megachilini and the evolution of leaf-cutter behavior in bees (Hymenoptera: Megachilidae), Journal of Melittology 2019 (85), pp. 1-123 : 56-57

Key to Extant Tribes of Megachilinae

(modified from Michener, 2007)

1. Metanotum with median spine or tubercle (except in Allodioxys Popov and Ensliniana Alfen ); mandible of female slender apically, bidentate, similar to that of male; pronotum (except in Prodioxys Friese ) with prominent obtuse or rightangular dorsolateral angle, below which a vertical ridge extends downward; sting and associated structures greatly reduced (scopa absent) ........... Dioxyini

—. Metanotum without median spine or tubercle; mandible of female usually wid- er apically, with three or more teeth, except rarely bidentate when mandible is greatly enlarged and porrect and clypeus is also modified; pronotum with dorsolateral angle weak or absent (or produced to a tooth in some Chelostoma Latreille but without vertical ridge below it); sting and associated structures well developed ........................................................................................................... 2

2(1). Pterostigma less than twice as long as broad, inner margin basal to r-rs usually little if any longer than width, rarely about 1.5× width; pretarsal claws of female cleft or with an inner tooth (except in Trachusoides Michener & Griswold ); body commonly with yellow or ivory integumental marks ...... 3

—. Pterostigma over twice as long as broad, inner margin basal to r-rs longer than width; pretarsal claws of female simple (except in Osmia subgenus Metalinella Tkalců, Palaearctic ); body without yellow or white integumental marks, except in Ochreriadini ................................................................................ 4

3(2). Outer surface of metatibia with long setae forming a distinct scopa; prestigma much more than twice as long as broad; preaxilla, below posterolateral angle of mesoscutum, sloping and with small patch of setae, these as long as those of adjacent sclerites ................................................ Aspidosmiini

—. Outer surface of metatibia usually with abundant simple bristles, not forming a distinct scopa; prestigma commonly short, usually less than twice as long as broad; preaxilla vertical, smooth and shining, usually without setae .... .......................................................................................................................... Anthidiini

4(2). Body distinctly elongate with enlarged pronotum surrounding mesoscutum anteriorly, thus practically eliminating omaular surface of mesepisternum and anterior surface of mesoscutum; body with yellow or ivory integumental markings at least on metasoma ........................................ Ochreriadini , n. trib.

—. Body not as elongate and slender as above, pronotum not enlarged nor surrounding mesoscutum anteriorly, mesepisternum with distinct omaular surface; body without yellow or white integumental marks .................................. 5

5(4). Outer surfaces of pro- and mesotibiae apically with an acute angle (usually produced into a spine) and distinct notch anteriorly; male T6 with preapical carina often present; arolia normally absent, except in a few tropical Old World taxa ( Noteriades , Matangapis , and Heriadopsis ); body nonmetallic or nearly so ...................................................................................... Megachilini

—. Outer surfaces of pro- and mesotibiae apically without an acute angle or spine and lacking distinct notch anteriorly; male T6 without preapical carina; arolia present; body sometimes metallic green, blue, or brassy .................. 6

6(5). Maxillary palpus with two palpomeres; propodeum with basal area not marked posteriorly by a strong carina, if present, it does not extend laterally behind propodeal spiracle; male T7 large, exposed, quadrately surrounded by T6; male S5 with modified discal setae (female: T6 with wide apical hyaline rim, S1 with slender, erect spine, posterolateral angle of mesoscutum with marginal ridge rounded or carinate, if rounded, with dense patch of long setae laterally) ............................................................................... Pseudoheriadini , n. trib.

—. Maxillary palpus with at least with three palpomeres; propodeum with basal area not marked posteriorly by carina, or if present, then extending laterally behind propodeal spiracle; male T7 small, usually hidden, not quadrately surround- ed by T6; male S5 with branched or simple discal setae ...................... Osmiini