Chlerogella Michener, 1954

Engel, Michael, 2010, Revision of the Bee Genus Chlerogella (Hymenoptera, Halictidae), Part II: South American Species and Generic Diagnosis, ZooKeys 47 (47), pp. 1-100 : 8-9

Genus Chlerogella Michener

Chlerogella Michener, 1954: 75 . Type species: Chlerogella elongaticeps Michener, 1954 , by original designation and monotypy. Eickwort, 1969: 445; Engel, 1998: 110; Engel, 2000: 38; Michener, 2000: 389; González et al., 2005: 50; Michener, 2007: 405; Smith-Pardo and Vélez-Ruiz, 2008: 57.

Diagnosis. Female: Head longer than wide; mandible with weakly to moderately developed subapical tooth; labral distal process narrowly triangular; basal elevation orbicular to bilobed; lateral teeth absent; prementum not greatly elongate, less than seven times longer than wide; galeal apex lobed; galeal comb absent; galeal base reaching back to stipital base; hypostomal ridge carinate to lamellate; anterior angle rounded; malar length usually much longer than basal width of mandible although in a few species the malar space is as long as to much shorter than basal mandibular width (vide infra); epistomal sulcus acute to nearly orthogonal; ocelli not greatly enlarged; ocellar furrow absent; vertex not expanded or ridged behind ocelli; preoccipital ridge round- ed. Pronotal dorsal surface typically unmodified from most genera with dorsal ridge rounded and medially overlapped by mesoscutum (rarely inflated between lateral portions of pronotal dorsal surface so that there is a long horizontal surface with a gently rounded anterior edge dropping down onto pronotal collar); lateral ridge entirely absent; mesoscutal anterior border rounded; tegula oval; prosternum expanded, pushing posterior corners of propleurae and anterior corners of procoxae apart. Probasitarsal brush present; metabasitibial plate bordered on all sides, not strongly rimmed; inner metatibial spur with pectinate branches along rachis, with eight or fewer branches. Forewing marginal cell apex acute; hind wing with distal hamuli irregularly spaced (typically arranged 2-1-2 or 3-1-2). Basal area of propodeum as long as or longer than combined lengths of mesoscutellum and metanotum, weakly to strongly imbricate; propodeal pit narrow, not set into broad V-shaped notch.

Male: Mandible simple; labrum without distal process; antenna long, reaching back to anterior through posterior borders of propodeum; second flagellomere longer than first flagellomere. Inner metatibial spur typically serrate, rarely ciliate or pectinate with short, thin branches. Metasoma typically elongate; SVII and SVIII with medio-apical projections; spiculum present and narrow; ventral surface of penis valve with prong; parapenial lobe absent; basal process of gonostylus absent; dorsal process of gonostylus typically reduced, with variable development of setae (typically with thickened elongate setae branched at their apices); ventral gonostylar process typically elaborately developed, with numerous sometimes thickened setae forming patches or fringes (secondarily simplified in a few species).

Comments. Some of the features historically believed to be of critical importance for defining Chlerogella are now understood to be rare among the diversity of species. For instance, the long and convex pronotal dorsal surface in C. elongaticeps is rare in the genus and does not fully characterize the clade. Similarly, the elongate malar space, while common across the genus, is not universal. Some of the more important characters that do hold are the elongate propodeum lacking striae or granular integument, the complete absence of the pronotal lateral ridge, a head that is longer than wide, a pectinate inner metatibial spur with eight or fewer branches, and an acute marginal cell. The related genus Chlerogelloides differs in that its species have a strongly acute epistomal sulcus that projects deeply into the clypeus as a thin lobe nearly reaching the clypeal apex and has a serrate inner metatibial spur in females, and a strongly doublecurved simple mandible, a shorter antenna, and the first flagellomere longer than the second in males. From Ischnomelissa the genus differs in the fewer branches of the inner metatibial spur (10 or more densely packed branches in Ischnomelissa ) in females and the more elaborately developed gonostylar processes in males. All three of these genera share an expanded, diamond-shaped prosternum. In addition, the elongate propodeum lacking striae is common to these genera and the species of Chlerogelloides share with at least C. elongaticeps the inflated pronotal dorsal surface.

Distribution. The genus is distributed in the Andean region from Bolivia, through Perú and Ecuador, into Colombia, from there across to Venezuela (Maps 1–5), and northward into Central America as far North as Guanacaste Province, Costa Rica (refer to maps in Engel 2009a).

Floral records. MELASTOMATACEAE : Clidemia crenulata Gleason ( C. clidemiae Engel ); ORCHIDACEAE : Phragmopedium longifolium (Warsz. & Rchb.f.) Rolfe ( Orchidaceae ) ( Chlerogella sp., identification of bee has not been confirmed as the material upon which the determination was made is unknown); RUBIACEAE : Psychotria pongoana Standl. ( C. hypermeces sp. n.). One label of a female of C. oresbios collected in Venezuela indicates the specimen was captured at flowers of “Corupelis”. I have not been able to determine what plant genus this was intended to correspond to.