♀, Colombia: Magdalena, Santa Marta, via a Nenguange, cerca a Bonda [11°24'N, 74°12'W], Enero 3, 2007, J. Florez. Deposited in the Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia.

The female of this species belongs to the neotropicus species group sensu Michener (2007) mainly distinguished by the coarsely pectinate inner metatibial spur and weakly developed sternal scopa. It can easily be recognized by the following combination of characters: inner metatibial spur with few, elongate branches (Fig. 5); scutum uniformly punctate, with coarse punctures separated by a puncture width or less (Fig. 3); metasomal terga largely impunctate, with minute, faint, scattered punctures, without integumental or apical hair bands (Fig. 4); body pubescence ferruginous; and tibial scopa with sparse, long (2.5–3.0 times median ocellar diameter), apically branched hairs. Among species of the neotropicus group, Leioproctus rosellae resembles those having an inner metatibial spur with few (8 or less), elongate branches such as the Argentinean species Leioproctus neotropicus (Friese) and Leioproctus stilborhinus (Moure). However, those species have a different combination of characters, have the clypeus and scutum sparsely punctate, and the metasomal terga more coarsely and densely punctate than in Leioproctus rosellae.

Female: Body length 6.56 mm; forewing length 5.0 mm; head width 2.23 mm. Head 1.2× wider than long; inner orbits of compound eyes slightly converging below (Fig. 2); intertorular distance 1.6 times median ocellar diameter, 1.2 times length of torulorbital distance; torulus diameter subequal to median ocellar diameter; ocellocular distance 2.5 times median ocellar diameter, 1.8 times greater than ocelloccipital distance; interocellar distance subequal to ocellocular distance, about 2.4 times median ocellar diameter; compound eye about twice as long as broad; clypeus about twice as broad as long, flat in profile view; gena 0.8 times narrower than compound eye in profile; supraclypeal area gently convex; frontal line distinct, carinate just above inferior torular margin to one-half distance between upper torular margin and median ocellus, ending at that point; facial fovea absent; scape 4.1 times longer than broad; antennal flagellum about twice as long as scape; pedicel subequal to first flagellomere, slightly longer than broad, first flagellomere 1.2 times longer than broad, about twice as long as F2 and F3 individually, remaining flagellomeres broader than long, except last flagellomere longer than broad; glossal lobes broader than long; labial palpus four-segmented; maxillary palpus six-segmented. Propodeum with subhorizontal basal area about as long as metanotum, marginal groove continuous, not pitted; protibial spur with apical portion of rachis long, about half of malus length, with distinct row of 5 elongate branches (not including apical portion of rachis); basitibial plate with apex rounded; mesotibial spur gently curved apically, ciliate, more than one-half of mesobasitarsus length; inner metatibial spur straight, pectinate (Fig. 5), with distinct row of 7 elongate branches on left spur, 5 on right spur (not including apical portion of rachis); pretarsal claws cleft, inner ramus shorter than the outer; arolia present in all legs; forewing with basal vein distal to cu-v.

Color black, except outer surface of mandible and anterior surface of antennal flagellum yellowish and the following areas light to dark reddish brown: antennal scape, tegula, legs excluding coxae and trochanters, and metasoma. Wing membranes brownish, veins and pterostigma dark brown.

Pubescence light ferruginous, whitish on face. Head with short (less than median ocellar diameter), sparse, plumose hairs except long (≤ 2 times median ocellar diameter), simple, stout hairs on preapical margin of clypeus. Pronotal lobe, mesepisternum dorsally, scutum, scutellum, and metanotum with strongly plumose hairs partially obscuring integument; hairs long (≥ 2 times median ocellar diameter) on scutellum, metanotum, posterior surface of propodeum, and mesepisternum ventrally; femoral and tibial scopa with sparse, long (2.5–3.0 times median ocellar diameter), apically branched hairs (cf. Michener 2007; fig. 13-1a); inner surface of metatibia with simple, shorter hairs than on scopa. Metasomal terga mostly bare, with scattered, minute (~0.2 times median ocellar diameter), erect simple hairs on discs, hairs becoming longer, denser and branched towards apical terga, longer and denser on fifth and sixth terga (Figs 1, 4); second to fifth metasomal sterna distally with long (about 3 times median ocellar diameter), poorly branched hairs.

Integument in general smooth and shiny between punctures, weakly imbricate on metasomal sterna. Outer surface of mandible with sparse, minute punctures; clypeus with larger punctures than on mandible separated by 1–2 times a puncture width; supraclypeal area with sparser punctures than on clypeus; subantennal area and inferior paraocular area with punctures separated by a puncture width; frons with small punctures separated by 1–2 times a puncture width, punctures becoming smaller towards interocellar area; vertex with coarse punctures separated by a puncture width or less; gena with faint, small punctures separated by more than two times a puncture width. Scutum uniformly punctate, punctures coarser than on vertex, separated by a puncture width or less; scutellum sparsely punctate on disc; axilla with small punctures separated by a puncture width or less (Fig. 3); metanotum with large punctures as on scutum separated by a puncture width or less; mesepisternum with punctures separated by more than two times a puncture width; metepisternum minutely punctate. Propodeum impunctate basally, posterior surface with coarse, scattered punctures, punctures becoming sparser and faint on lateral surface. Metasomal terga largely impunctate, with minute, faint, scattered punctures on discs, punctures coarser and denser on fifth tergum; distal margins of terga shiny, smooth and impunctate except on apical terga; sterna with coarse, scattered punctures.

Male: Unknown.

This species is named after my newly born daughter Rosella Amparo Betancourt, who was born July 28, 2011, and has already brought us immeasurable love and joy.

The holotype is in somewhat poor condition. The left foreleg is missing, the distal margins of the wings are worn out, and the hairs are plastered against the integument (Fig. 1). It is likely that Leioproctus rosellae also occurs along the valleys of the Magdalena and Cauca rivers where tropical dry forests occur. Such a distribution pattern is exhibited by some solitary (e.g., Anthidium sanguinicaudum Schwarz) as well as social bees [e.g., Melipona favosa (Fabricius), Frieseomelitta paupera (Provancher)] that also inhabit the same type of forests (Gonzalez, personal observations).