Extracted from: Timberlake P.H., (1962). A Revisional Study of the Bees of the Genus Perdita F. Smith, with Special Reference to the Fauna of the Pacific Coast (Hymenoptera, Apoidea) Part V. University of California Publications in Entomology Editors, Volume 28, No. 1, pp. 1-124.|
Only the male of this little bee, a visitor of Compositae in New Mexico, is known, and it has been recorded only from Las Cruces, the type locality, and from Albuquerque, at flowers of Gutierrezia and Aplopappus. It is distinguished from others of its group by the restriction of yellow face marks, as described below.
Male.—Head and thorax dark green; propodeum bluish; disk of mesonotum and scutellum black. Mandibles except reddish tips, labrum, clypeus, lateral marks, and sometimes anterior end of gular region and of cheeks, yellow. Pair of dots on clypeus small and usually faint. Lateral face marks broad at anterior end, tapering gradually to a blunt point that touches foveae (in one small-headed specimen ending at level of antennae). Thorax entirely dark. Abdomen pale fuscous or brownish above, yellow beneath, and with a broad, nubilous, yellow band at base of tergites 2 to 4 or 5, that on tergite 2 enclosed. Front and middle legs yellow, with femora fuscous on posterior side except at apex; hind legs fuscous, with trochanters and apex of femora yellow, tarsi brownish. Antennae fuscous above, becoming more brownish toward apex; scape clear yellow; flagellum brownish yellow beneath. Tegulae yellow at base, broadly hyaline on outer margin. Wings milky hyaline, nervures pallid, subcosta and margin of stigma pale yellowish.
Head small and rotund to moderately enlarged and quadrate; cheeks broad but strongly receding and obtusely angled anteriorly in the more macrocephalous examples. Occipital concavity moderately deep, but not as wide as space between summit of eyes in small-headed specimens. Proboscis moderately long, slightly exceeding the fossa in repose. Mandibles long, slender, tapering, very acute at apex, and each reaching almost to base of the other in more-macrocephalous examples. Facial foveae faint and punctiform. Face below level of antennae strongly convex from side to side; disk of clypeus about as high as wide; lateral extensions moderately reflexed and visible in frontal aspect. Flanks of pronotum sometimes deeply impressed, posterior corners of disk prominent and rounded. Pterostigma hardly more than one-half as broad as first submarginal cell; part of marginal cell beneath it longer than part beyond. Head and thorax shining, impunctate; mesoscutum and scutellum polished, or margins of scutum faintly tessellate; frons and vertex with moderately strong and minute tessellation. Pubescence white, sparse, moderately long, and erect on face, vertex, cheek, and anterior border of mesoscutum, comparatively long and dense on undersurface of head and thorax. Tergite 7 with a moderately narrow and rounded apex. Subgenital plate somewhat more than twice as long as wide at truncate apex, broadening toward base, and minutely pubescent on disk. Caulis of aedeagus as long as wide, with dorsal lobes meeting and ending acutely in median line as seen from above and rather strongly obtuse at apex in lateral view; volsellae well exposed; parameral lobes moderately long, incurved, and tapering to rather acute apex; sagittae slenderly fusiform, the rods separated but hardly divergent, each slender and nearly uniform in width. Length: about 3-4 mm., anterior wing, 2.5-2.7 mm.