Species account taken from: "A Revision of the Genus Ashmeadiella (Hymen., Megachilidae) Author(s): Charles D. Michener Source: American Midland Naturalist,Vol. 22, No. 1 (Jul., 1939), pp. 1-84"
Heriades opuntiae Cockerell, 1897, Ann. Mag. Nat. Hist., (6)20:139, Y. Eriades opuntiae Friese, 1911, Das Tierreich, 28:29, 9. Ashmeadiella opuntiae Cockerell, 1897, Ent. News, 8:197; Cockerell, 1898, Bull. Denison Univ., 11:64 (key); Cockerell, 1898, Bull. Univ. New Mex., 1:64 (key); Cockerell, 1900, Am. Nat., 34:488 (record); Michener, 1936, Am. Mus. Nov., 875:4, 8. Ashmeadiella submaxima Michener, 1936, Am. Mus. Nov., 875:3, a.
This species is large, robust, black, and rather sparsely pubescent. The broad mandibles and long clypeal truncation seem to indicate a relationship with Titusella.
Female: Transfacial line about as long as facial; inner margins of eyes harly converging below; under side of flagellum dusky or brown; truncation of clypeus longer than distance from end of truncation to lateral angle of clypeus; truncation demarked laterally by distinct, slightly produced angles, so that truncation is somewlhat concave; anterior fourth of clypeus, except for the smooth margin, finely and closely punctate; disk of clypeus with punctures coarse and separated by about their diameters to nearly twice their diameteis; anterior ocellus at or near midpoint between antennal bases and posterior edge of vertex; cheeks as broad as or a little broader than eyes, seen from side; mandibles with distance from first to third tooth about as long as greatest width of eye, longer than length of last three antennal segments together; dorsal carina of anterior edge of mandibles ending nearer anterior basal angle than posterior basal angle of mandible; distance between posterior ocelli less than distance to nearest eye margin, which distance is less than distance to posterior edge of vertex; punctures of head except clypeus and of thorax finer than those of disc of clypeus and rather close, those of vertex a little coarser than those of scutum; no pair of hair spots at anterior end of scutum; punctures of mesepisterna slightly finer than those of scutum; tegulae piceous; claw segments of tarsi slightly rufescent; inner margin of inner hind tibial spurs finely serrate with about eighteen small teeth, outer margin with about seven teeth, the median ones of which are long and slender; inner and outer margins of outer spurs with about six and eight somewhat oblique teeth respectively; abdomen strongly punctured; apical pubescent band of fifth tergite usually distinct, sometimes weakened or apparently absent (perhaps worn); scopa white. Length 8 mm.
Male: Similar to female. Transfacial line longer than facial; inner margins of eyes with lower parts diverging toward clypeus; anterior margin of clypeus with broad, shallow emargination, a little shorter than basal width of clypeus, delimited laterally merely by a broad, rounded angle on each side; cheeks as wide as eyes or nearly so. Inner margin of inner hind tibial spurs finely serrate, outer margin with a few coarse teeth; inner margin of outer spurs with two low, oblique teeth, outer margin with about six, small, inconspicuous, oblique teeth. Sixth tergite with lateral teeth long, pointed apically; median teeth over twice as long as basal width, concavity between them considerably longer than semicircle. Punctation similar to that of female, but punctures of vertex a little coarser, those of disc of clypeus finer; subapical finely punctate band of clypeus narrower; clypeus and supraclypeal area not densely covered with hair, as in many males; fifth tergite without apical pubescent band. Length 7 to 9 mm.
This is a species of the arid regions from Texas and southern Colorado to California and Sonora, and is apparently an oligotropic visitor of the flowers of cactus.
TEXAS: Cotulla, on Opuntia, May 10, 1906 (J. C. Crawford, U. S. N. M.) ARIZONA: Santa Rita Mountains, August 18, 1935 (E. I. Beamer, Univ. of Kansas). SONORA: Rio Mayo, July 10, 1935 (Bohart collction). CALIFORNIA: Cathedral City, Riverside County, on Echinocactus cplindraceus (E. G. Linsley, C. D. Michener); Palm Springs, April 2, 1937, on Opuntia echinocarpa; San Felipe Creek, Tune 5, 1936, on Opuntia megacarpa; Riverside, April 24, 1934, on Opuntia vaseqi; Whittier, March 13, 1926, on Opuntia; Clark Mountains, 4500 feet elevation, on Vigueria nevadensis (all P. H. Timberlake); Willow Springs, Kern County. Type: Female; Soledad Canyon, Organ Mountains, New Mexico.
Most Californian specimens have the anterior ocellus farther posterior than in specimens from the eastern part of the range. A possible subspecific separation is thus suggest