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. mentzeliarum was based on material from the Organ Mountains, New Mexico, in which the clypeal and lateral face markings of the female were well developed, and the yellow of the face of the male extended above the antennae in the median line, with the lateral marks extremely broad above. The variety lauta has the dark markings on the legs and abdomen reduced or sometimes almost absent. The type locality of mentzeliarum is Riley's Ranch, Organ Mountains, Dona Ana County, and the type locality of lauta is 5 to 6 miles above Tularosa, on the road to the mountains, Otero County.
Female.—Head and thorax dark green; supraclypeal area, subantennal plates, mesoscutum except anterior border, and scutellum, black. Mandibles except red tips, clypeus, triangular lateral face marks reaching level of foveae or intruding slightly between them and eyes, collar of pronotum, tubercles, and an almost continuous band on hind margin of pronotum between the tubercles, creamy white. Abdomen creamy white; base of tergite 1, apical band on tergites 1 to 3 (often more or less broken), and spot at basal corners of tergites 2 to 4, fuscous. Legs white; base of coxae, femora except at base and apex and more or less on dorsal margin, streak on outer margin of middle tibiae, and hind tibiae except ventral edge, fuscous. Labrum fuscous or brownish, antennae pale yellow, pedicel and flagellum faintly brownish above. Tegulae sub-hyaline, with a basal white spot. Wings milky hyaline, nervures very pallid, stigma yellowish. (In var. lauta, dark markings of legs and abdomen more or less evanescent. In females from Chihuahua, Mexico, recorded below, more or less white developed on supraclypeal area and subantennal plates, with face becoming almost entirely white below level of antennae in some specimens.)
Head as broad as long; clypeus broadly truncate above, between subantennal plates. Facial foveae a little wider than interval between them and eyes and reaching from level of middle of antennal sockets about two-thirds of distance to level of anterior ocellus. Mandibles with a small inner tooth and not quite reaching far margin of broad proboscidial fossa. Proboscis of moderate length, galeae in repose not reaching base of stipites. Pterostigma large, about three times as long as wide, and nearly as wide as first submarginal cell; part of marginal cell beneath stigma somewhat longer than part beyond. Pygidial plate plane, triangular, and rather narrowly obtuse at apex. Head and thorax minutely and rather delicately tessellate and moderately shining; face below antennae smooth and shining; frons and mesonotum with fine scattered punctures. Pubescence whitish; fine and sparse on face; short and erect on mesonotum, becoming somewhat dense on posterior border and forming faint prescutellar band. Length: about 5-5.5 mm.; anterior wing, 3.8-4 mm.
Male.—Dark parts of head and thorax dark green or bluish; disk of mesoscutum and scutellum black. Face yellow to level of foveae; dark color of frons usually extending as a triangular lobe to each antennal socket; yellow in median line sometimes reduced to a slender projection, butthat on sides of face ending broadly and often notched by foveae. Undersurface of head and cheeks yellow nearly to summit of eyes. Sides and undersurface of thorax yellow with a dark crossband on disk of pronotum, an oblique band (sometimes interrupted) from beneath tegulae to base of middle coxae, and a large circular dark mark on each side of posterior part of meso-pectus. Abdomen yellow, sometimes with base of tergite 1 and two subapical spots on same segment fuscous. Mandibles except red tips, labrum, antennae, and legs, yellow. Rarely a faint dark band at apex of tergites 2 and 3 and a duskiness on outer edge of hind tibiae. Tegulae and wings as in female.
Head in many smaller specimens small, with only moderately broad unarmed cheeks; but in some specimens greatly enlarged, quadrate, broader than long and broader than thorax, with lateral plates of face below antennae distinctly broader than space between them, and very broad cheeks either with or without an anterior tooth. Mandibles tapering, acute, and reaching far margin of proboscidial fossa. Facial foveae small and punctiform. Flanks of pronotum more or less deeply impressed in correlation with size of head; disk transversely impressed behind collar, with posterior corners becoming very prominent and rounded. Head and thorax shining and nearly polished; tessellation distinct only on frons, anterior part of mesoscutum, and pro-podeum. Pubescence much as in female. Tergite 7 narrowing from base to rather broadly rounded apex. Subgenital plate triangular, convex on ventral surface, and ridged apically almost as in wootonae. Genitalia much smaller than in mentzeliae or wootonae; dorsal lobes of caulis moderately wide and rounded at apex and nearly reaching apex of volsellae; parameral lobes slender, incurved at apex, and sparsely hairy; fused sagittae elongate oval as seen from above, with the rods not divaricate at apex. Length: about 3.5-4.8 mm.; anterior wing, 2.8-3.5 mm.