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.|
P. brevihirta is known only from Maricopa County, Arizona, where it has been taken at flowers of Pedis papposa. It is closely related to austini, but the male has the face entirely yellow below level of antennae, the disk of clypens more strongly dentate on each side of base of labrum, and the subgenital plate and genitalia distinctive.
Female.—Head and thorax dark green, without light markings; disk of mesoscutum, scutellum, and metanotum, black; labrum and clypeus, black or brownish. Abdomen dark, more or less tinged with brown, with a narrow pale-yellow or creamy-white band at base of tergites 2 to 5, not reaching lateral margins; pygidial plate ferruginous; venter brown. Legs brown; apex of femora, tibiae and tarsi of front legs, extreme apex of middle femora, and underside of middle tibiae and middle tarsi, pale yellow. Antennae blackish, flagellum yellowish beneath. Mandibles pale yellow, becoming red on apical fourth. Proboscis dark. Tegulae pale yellow at base, broadly hyaline on outer margin. Wings milky hyaline, nervures pallid, disk of stigma whitish.
Head about as broad as long; disk of clypeus large, slightly broader than high, and obscurely dentate on each side of base of labrum. Facial foveae short, broad, oval, more than twice as wide as narrow space between them and eyes, and reaching from a little above level of antennal sockets less than halfway to level of anterior ocellus. Mandibles gently curved, moderately slender, with a small inner tooth, and reaching far margin of proboscidial fossa. Proboscis moderately long, tip of galeae not quite reaching base of stipites in repose. Pterostigma large, four times as long as wide, and nearly as broad as first submarginal cell; part of marginal cell beneath stigma about twice as long as part beyond. Tarsal claw small, inner tooth minute. Pygidial plate longer than wide and evenly narrowed to moderately wide and truncate apex. Head and thorax shining, faintly tessellate; face below antennae, disk of mesoscutum, and scutellum, polished; face opposite antennae and anterior border of mesoscutum with extremely minute and sparse punctures. Pubescence short and white on lower sides of face; short, coarse,and erect on anterior border of mesoscutum; longer and denser on cheeks; long and finer on front coxae and mesopectus. Length: about 4 mm.; anterior wing, 3 mm.
Male.—Head and thorax blue green, becoming black on posterior half of mesoscutum and on scutellum. Anterior half of gular region, mandibles except red tips, labrum, face below level of antennae, yellow, with lateral marks extending broadly to f oveae. Thorax dark, except for yellow tubercles. Abdomen brown or pale fuscous; venter and band at base of tergites 2 to 3 or 4, yellow. Legs yellow; a blotch on posterior side of front and middle femora, middle and hind coxae, hind femora except broadly beneath and at apex, and outer side of hind tibiae, fuscous. Antennae yellow, pedicel and flagellum brown above. Tegulae and wings as in female, except subcosta and margins of stigma more or less pale brownish.
Head a little broader than long; cheeks more or less broad but strongly receding, and narrowed and unarmed anteriorly. Occipital concavity rather shallow and about as broad as space between summit of eyes. Disk of clypeus convex, broader than high, and with a small acute process on each side of base of labrum; lateral extensions strongly reflexed and thus only about one-half visible in frontal aspect. Flanks of pronotum moderately impressed. Venation, sculpture, and pubescence about as in female. Tergite 7 narrowed to a moderately wide median lobe rounded at apex. Subgenital plate nearly twice as long as wide, somewhat narrowed to slightly rounded apex and with rather dense minute hairs on disk. Aedeagus similar to that of exilis, but dorsal lobes of caulis somewhat divergent, with area on each side roundly and deeply excised to base of parameral lobes; parameral lobes rather short, somewhat tapering, and simple; volsellae small and not surpassing dorsal lobes; sagittae rather short, with the rods spread apart, and thinly fusiform in lateral view. Length: about 2.5-3.5 mm.; anterior wing, 2-2.3 mm.