Extracted from: Timberlake P.H., (1969). A Contribution to the Systematics of North America Species of Synhalonia (Hymenoptera, Apoidea). University of California Publications in Entomology Volume 57|
This species is similar in many ways to primiveris, another new species, with which it flies on the Mohave and Colorado Deserts, but albescens has the abdomen more completely covered with white pubescence than any other species.
Female.óBlack; small joints of tarsi and claws ferruginous; tibial spurs testaceous. Smooth, exposed apical margin of tergites 1 to 4 more or less brownish. Flagellum of antennae slightly reddened beneath. Pubescence of head and thorax dense, rather short and white; sometimes pale ochreous on notum of thorax. Pubescence of abdomen white, almost entirely short and tomentum-like on tergites 2 to 4, with large patch of similar hair on each side of disk of tergite 1; base of tergites 4 and 5 showing black hair when segments are extended; hair on middle of apical margin of tergite 5 and sides of tergite 6 fulvous brown. Hair of legs whitish, with scopal hair of hind legs pale ochreous and changing to ferruginous on inner side of basitarsi, to pale brown on outer side of front and middle tibiae, and to chocolate brown on dense tuft at apex of hind femora and hind basitarsi. Tegulae pale amber, basal margin fuscous. Wing slightly dusky, nervures dark ferruginous, subcosta black.
Head broader than long; inner orbits slightly divergent above. Vertex only slightly impressed on each side between ocelli and eyes. Lateral ocelli about their distance apart from nearest eye and much closer to occipital margin. Clypeus moderately shining, with small shallow punctures, becoming finer and denser on anterior border, and with low, smooth, longitudinal ridges more or less anastomosing, and with more or less of a small, smooth space at middle of base. Meso-scutum shining, finely and closely punctured, becoming more polished on posterior middle of disk with punctures well separated. Posterior face of propodeum enclosed by arcuate divergent carinae, slightly curving inward above. Apical margin of tergites 1 and 2 with moderately wide, hairless, impunctate space. Second submarginal cell receiving recurrent nervure about one-fifth to one-fourth of its length from apex. Length 11-13 mm, anterior wing 8.8-9.5 mm, width of abdomen 4.7-5 mm.
Male.óBlack; tarsi and claws ferruginous; tibial spurs pale testaceous; apical margin of abdominal segments rufotestaceous. Labrum, clypeus, supraclypeal mark, and often a small spot at base of mandibles creamy white; clypeal mark almost touching margin of eyes, notched on each side, and broadly truncate at summit; supraclypeal mark small, triangular, and wider than high. Pubescence white, dense, and rather long on cheeks, thorax, and basal tergite of abdomen, short and appressed on tergites 2 to 6, and becoming denser and more tomentose to form narrow bands close to apex of tergites 3 to 6 and on each side of disk of tergite 2, and black at base of tergites 4 to 6. Hair tinged with brown on tergite 7 and on middle of sternites 4 and 5. Hair of legs white, but ferruginous on inner side of tarsi. Tegulae and wings as in female.
Head broader than long; inner orbits moderately divergent above, with facial quadrangle as long as wide. Antennae slender, moderately compressed, reaching apex of tergite 2, joint 3 about twice as long as wdde on short side and about one-third as long as joint 4 on long side. Mesoscu-tum shining, strongly and densely punctured, with punctures more separated on posterior middle of disk. Middle tibiae normal, tibiae densely pubescent on inner side. Sternite 6 weakly impressed on each side toward base, apical margin rounded and bordered with close-set, appressed yellowish hairs, and base with thin erect hair. Parameral lobes of genital armature moderately long, slightly bowed, triangularly dilated at base, widened on inner side at apex and invested with fine, pale hair on outer face. Length about 11 mm, anterior wing 8.5-9 mm.