Species account taken from " A Revision of Perdita (Xerophasma) Timberlake (Hymenoptera: Andrenidae) Authors: TERRY GRISWOLD & WENSDAE MILLER Source: Zootaxa, Vol. 2517 (June 24, 2010) pp 1-14"
Female. Length: 7.0–7.5 mm. Forewing length: 5–5.5 mm. Head, mesosoma pale caramel-colored except: most of face cream-colored; dark-brown longitudinal mark above antennal socket, interocellar area, ventral area of mesepisternum; brown lateral longitudinal mark on mesoscutum, U-shaped mark on propodeum. Costal vein, prestigma dark. Stigma slightly stained, ventral margin distinctly darkened. T1–3 with subapical brown bands widened laterally on otherwise caramel-colored terga, on T4 reduced to lateral spot. Frons shiny. Mesoscutum impunctate, with sparse long pale hair present only anteriorly and laterally. Mesoscutum, scutellum shiny. Propodeal triangle somewhat shiny, finely reticulate.
Mandible simple, without preapical tooth. Labrum with apical margin slightly convex. Clypeal width dorsally slightly greater than width of each subantennal area. Frontal line scarcely raised, grooved. Facial fovea dull, linear, densely pubescent, extending from middle of antennal socket two-thirds distance to median ocellus. Ocellar area not inflated. Median ocellar diameter 1/6 width of interocular distance at level of median ocellus. Length of vertex behind lateral ocellus greater than ocellar diameter. Forecoxa, mesepisternum ventrally with long, simple, erect, apically bent hair. Length of marginal cell on wing margin less than or equal to 1.5 apical width. Pygidial plate broadly truncate.
Male. Length: 5.5 mm. Forewing length: 4 mm. Head, mesosoma, legs pale caramel-colored except: entire face yellow; dark brown between ocelli, posterior to eye, longitudinal line laterally on mesoscutum, propodeum dorsally and posteriorly; brown subapical band on T1, less distinct bands on T2–4 broadened into spots laterally. T2 lateral fovea sometimes forming fine dark line. Sculpture, punctation, pubescence as in female except clypeus densely punctate.
Clypeal width dorsally approximately two times greater than width of each subantennal area. Supraclypeal area conically protuberant, with tuft of erect, apically bent hair. Facial fovea pubescent, elliptical, minutely depressed, equidistant from level of ventral margin of median ocellus and dorsal margin of antennal socket.
Frontal line, ocellar diameter, forewing as in female. T7 with pygidial plate well defined, with apical tuft of hair protruding from beneath apical margin. S8 as in Fig. 20. Genitalia as in Figs. 10, 15.
Type material. Holotype female: USA California, Inyo Co., Stovepipe Wells, 1.76 mi ENE; Stovepipe Main Dunes, near S margin, 11S E489743 N4051323, 26 Apr 2003, Camissonia, T. & R. Griswold. Paratypes:6 males, 2 females, same data as holotype. Holotype is the property of the National Park Service and is indefinitely deposited in the U.S. National Pollinating Insects Collection, Logan, Utah; paratypes in Logan and the Death Valley National Park collection.
Diagnosis. Females with head more robust than in other Xerophasma, with the vertex longer. The conical protuberance and tuft of hair on the supraclypeal area in the male is not found in other Xerophasma or elsewhere in the genus.
Range. Apparently endemic to Death Valley (Fig. 23). Known only from dunes near Stovepipe Wells where it was active at dusk.
Variation. The size of the dark markings varies slightly in both sexes.
Etymology. This species was discovered after we thought we had completed this manuscript. It is a great pleasure to name this bee after my wife Rhonda, who has been my companion on many an entomological quest, and who discovered these bees on Camissonia as we were leaving the dunes near Stovepipe Wells at dusk.