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Extracted from P. H. Timberlake. 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 Press Berkeley and Los Angeles 1962 This species is closely allied to dasylirii and the males of the two species are rather difficult to distinguish, but the female of polytropica has the mesonotnm uniformly dark green and tessellate, and duller than in dasylirii. The male has the mesonotum also duller and clothed with coarser, more conspicuous, but sparse white hair. The two species fly together in some localities in Arizona and both have been taken on the same day in Sabino Canyon, Santa Catalina Mountains, where they were probably visiting the same flowers. I have divided polytropica into two subspecies: the light markings of face and abdomen are distinct in the typical form, but are usually absent or more or less evanescent in obsoleta.
Perdita polytropica polytropica, n. subsp.
Female.—Head and thorax dark green, supraclypeal area blackish. Mandibles and clypeus yellowish white; mandibles shading into red at apex, clypeus with two brown or blackish stripes more or less developed on disk. Labrum testaceous, but more or less infuscated at base. Collar of pronotum and tubercles, pale yellow. Abdomen brownish fuscous; pale yellow band at base of tergites 2 to 4 or 5, and sometimes a quadrate mark at summit of basal declivity of tergite 1; lateral margins of basal half of tergite 1, lateral margins (except basal corners) of tergites 3 to 5, and venter, including reflexed ventral part of tergites, pale yellow. Legs yellow; streak on posterior side of front femora and middle tibiae, extreme apex of hind femora, and hind tibiae and tarsi, brown. Antennae brownish fuscous; scape pale yellow beneath, flagellum more brownish yellow beneath. Tegulae hyaline, with yellow base. Wings whitish hyaline, nervures pale testaceous, subcosta and margins of stigma slightly brownish.
Head orbicular, as wide as long; inner orbits nearly parallel. Proboscis moderately short, apex of galeae reaching about halfway to base of stipites in repose. Mandibles rather narrow and curved, with a well-developed inner tooth and blunt apex. Facial f oveae about their own width from margin of eyes and reaching from level of upper margin of antennal sockets less than halfway to level of anterior ocellus. Pterostigma as broad as first submarginal cell, hardly more than two and one-half times as long as broad; part of marginal cell beneath it much longer than part beyond. Pygidial plate about as long as wide at base, sides converging to rather narrow and rounded apex. Head and thorax nearly uniformly and finely tessellate and moderately dullish, with fine and moderately close punctures on face, becoming sparser on clypeus; numerous but well-separated fine setigerous punctures on mesonotum. Pubescence white, thin and short, that on mesonotum coarse, erect, and somewhat squamif orm, and on undersurf ace of head and thorax longer and denser. Length: 4-4.5 mm.; anterior wing, 3.2-3.5 mm.
Male.—Head and thorax yellow; vertex and middle of occiput, transverse mark on disk of pronotum, mesoscutum except lateral margins, seutellum, metanotum, and propodeum except the flanks, dark blue-green. Yellow of face almost reaching level of anterior ocellus; dark band across vertex narrowed toward summit of eyes and less narrowed toward occiput. Abdomen yellow; tergite 1 except a mark at summit of basal declivity deeply notched in front, and a rather narrow even band at apex of tergites 2 to 5 (more or less arcuate on tergite 2), brown or fuscous, a faint subapical band on tergite 6. Legs yellow; apex of hind femora above, hind tibiae except beneath, and hind tarsi, brown or fuscous, often a narrow dark streak on middle tibiae. Antennae yellow; a fuscous spot on pedicel and on several following joints of flagellum. Tegulae and wings as in female, but nervures less pallid.
Head orbicular, slightly broader than long; cheeks broad, but receding, widest opposite posterior half of eyes, and unarmed. Mandibles tapering from broad base and reaching well beyond far margin of proboscidial fossa. Facial foveae punctiform. Flanks of pronotum about normally impressed. Head and thorax finely and delicately tessellate, and slightly dullish; face impunctate, and setigerous punctures of mesonotum sparser than in female. Pubescence thin and white: face and cheeks nude; hair on underside of head dense but rather short, lengthening only slightly toward occiput; hair of vertico-occipital border of head and of mesonotum distinctly squamiform, longer than in female and more depressed on mesoscutum. Tergite 7 narrowed to rather broadly truncate apex. Subgenital plate quadrate, about one and one-half times as long as wide, truncate at apex, and with hair on apical part of disk short and very fine. Genitalia much as in allied species, but volsellae well exposed in dorsal view, dorsal lobes of caulis short, and fused apical part of sagittae as seen from above much more nearly uniform in width than in rhois or dasylvrU. Length: 3.5-4.5 mm.; anterior wing, 2.4-2.9 mm.
One female, Surprise Canyon, Panamint Mountains, California, has the labram, elypens, and supraclypeal area blackish, and the yellow bands on tergites 3 and 4 interrupted. Two other females from the same locality are typical. Females from Gila Bend, Arizona, and eastward have the clypeus more or less dark except for a yellow streak on middle of disk, and the yellow bands of abdomen narrow and usually restricted to tergites 2 and 3. Females from the Grand Canyon, Arizona, have an entirely yellow clypeus and small lateral face marks.
Perdita polytropica obsoleta, n. subsp.
Female.—Distinguished from typical polytropica by having the face and abdomen often entirely dark. Clypeus often brownish, sometimes with a small median yellowish spot or streak, and abdomen rarely at type locality with a more or less narrow abbreviated, or interrupted, yellow band at base of tergites 2 to 4. Mandibles except red tips, collar of pronotum and tubercles, basal corners of tergites 3 and 4, and reflexed ventral part of these and other tergites, normally pale yellow or whitish. Legs mainly dark; trochanters of all legs, apex of front femora, front tibiae except sometimes a streak on posterior margin, front tarsi, apex or sometimes a large part of middle femora, and anterior side of middle tibiae, pale yellow. Antennae dark, scape not yellow beneath as in polytropica. Pygidial plate rufotestaceous. Length: about 4r-4.5 mm.; anterior wing, 3.3-3.5 mm.
Male. — Not differing materially from typical polytropica.
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