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.|
Cockerell described this species from a single female collected from flowers of Chrysothamnus at Embudo, New Mexico, in September, 1897. This female has an enclosed yellow band at base of tergites 3 to 5. Of two females collected at Eureka, Utah, one has a band at base of tergites 2 to 5, and the other a band at base of tergites 3 and 4 and a trace of band on tergite 5. A single female collected near Camp Verde, Arizona, has only a much abbreviated and interrupted band (or two transverse marks) at base of tergite 4. Males collected in Utah, Arizona, and Nevada show no variation in markings.
Female.—Head and thorax dark green or bluish green; posterior half of mesoscutum and scutellum more or less blackish; labrum and clypeus brown or black. No light markings except a narrow yellow band on collar of pronotum. Mandibles dark rufotestaceous, sometimes with a yellowish spot. Abdomen fuscous or black, with an abbreviated enclosed yellow band at base of tergites 2 or 3 to 4 or 5, or sometimes only on tergite 4; these bands end for from lateral marginsand cover about one-fourth to one-third of length of segments. Pygidial plate pale ferruginous. Legs blackish; front knees, anterior side of front tibiae, front and middle tarsi, and sometimes small joints of hind tarsi, yellowish. Antennae dark brown or fuscous, nagellum paler beneath, radicle joint of scape yellowish. Tegulae hyaline, with a yellow mark at base. Wings whitish hyaline, nervures pallid, margins of stigma and subcosta testaceous or brownish
Head as broad as long, with inner orbits parallel. Clypeus large, convex, and broadly rounded on upper margin. Facial foveae will impressed and reaching about halfway from upper level of antennal sockets to level of anterior ocellus. Proboscis of moderate length: galeae equaling stipites, maxillary palpi with six long joints. Mandibles convex on outer side, concave within, strongly curved, obliquely truncate at apex, and width about one-fourth of length of inner margin. Pterostigma about equaling width of first submarginal cell; part of marginal cell beneath stigma generally longer than part beyond, the latter part as broad as long. Pygidial plate about as long as broad at base and narrowed evenly to moderately narrow ogival or obtuse apex. Head and thorax more or less weakly tessellate and moderately shining, frons nearly impunctate, mesoscutum with sparse weak punctures. Pubescence whitish, thin, short, and erect (more squamiform on mesonotum in Arizona specimen); longer and denser on cheeks and underparts of thorax. Length: about 4r-5 mm.; anterior wing, 2.9-3.3 mm.
Male.—Head and thorax dark green; undersurface of head, anterior three-fourths of cheeks, and face to level of foveae, bright yellow. Pronotum except triangular mark on disk, prosternum, broad median part of mesopectus, and nearly anterior half of mesopleura, yellow. Abdomen yellow, with tergite 1 fuscous, and a dark band at junction of following segments, those at junction of tergites 3-4 and 4r-5 abbreviated or evanescent. Legs and antennae entirely bright yellow. Proboscis and mandibles yellow, latter briefly red at apex. Tegulae and wings as in female, except subcosta, margins of stigma, and nervures enclosing marginal cell, more brownish.
Head as broad as long, nearly rotund, and slightly broader than thorax. Cheeks strongly receding, somewhat broader than eyes and rounded beneath. Face below antennae strongly convex from side to side, lateral extensions of clypeus partly exposed to view in frontal aspect of head and tapering to outer ends. Mandibles broad at base, tapering to finely pointed tips and reaching well beyond far margin of proboscidial fossa. Antennae rather short, flagellum clavate, scape obconical and not quite reaching the nearer eye margin. Face and foveae punctiform. Head and thorax faintly tessellate, impunctate, and more shining than in female; face, disk of mesoscutum, and scutellum almost polished. Pubescence sparser than in female: face and disk of mesoscutum and scutellum nearly nude, but hair of cheeks and underparts of thorax rather dense. Tergite 7 narrowed to a median lobe about as long as wide and truncate at apex. Sub-genital plate about at long as wide, with sides moderately converging to rounded apex, apical part of disk with very fine and short pubescence. Dorsal lobes of caulis very acute and about reaching level of middle of parameral lobes; latter rather slender and with fine sparse pubescence at apex; volsellae well exposed beyond apex of dorsal lobes; sagittae strongly fusiform in apical part, widest near beginning of last fourth of the length, then narrowing to obtuse apex as seen from above, thickest in lateral view near middle, and subacute at apex. Length: about 3 mm.; anterior wing, 2.3 mm.