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"
Ashmeadiella timberlak?ei Michener, 1936, Pan-Pac. Ent., 12: 56, 9 ; Michener, 1936, Am. Mus. Nov. 875:12, 14. (Key).
This is a black species, with the abdomen largerly red. It is closely related to lutzi but has a shorter median lobe of the clypeus in the female.
Female: Inner margins of eyes about parallel; under side of flagellum brownish; facial line a little longer than transfacial; clypeus rather coarsely punctate, punctures rather close or separated medially by some shiny surface; margin of clypeus trilobed, lateral lobes separated from median by broad V-shaped notches; lateral lobes rounded at apices, not greatly shorter than median lobe; median lobe itself bilobed at apex; apex of labrum strongly bidentate; mandibles with apices reddish; hypostomal carinae each produced to a tooth behind; cheeks nearly as broad as eyes, seen in lateral view; anterior ocellus much posterior to midpoint between antennal sockets and posterior edge of vertex; distance between posterior ocelli equal to distance to nearest eye margin and to posterior edge of vertex; frons and vertex rather closely punctate. Scutum punctured similarly to vertex, without spots of pubescence anteriorly; tegulae testaceous, wings slightly dusky; hind femora and inner sides of hind tibiae red; inner margin of inner hind tibial spurs serrate with about eighteen small teeth, outer margin with seven or eight long teeth; inner margin outer spurs with about seven oblique teeth, median ones largest, and sometimes one or two additional basal teeth, outer margin serrate with about nine small teeth. Abdomen strongly punctate, dorsum of second tergite with punctures separated by about their diameters (usually); punctures laterally and on posterior tergites close; sides of abdomen, back to sixth tergite, red, this color much more extensive on anterior tergites than on posterior ones, and much reduced on sixth tergite; tergites one to five with apical bands of white pubescence. Length 5.5 to 6.5 mm.
Male: Inner margins of eyes converging toward clypeus, except for lower portions which diverge; transfacial line a little longer than facial; clypeus not covered by white pubescence; anterior margin of clypeus truncate, truncation concave and nearly as long as basal width of clypeus; apex of labrum slightly bilobed; anterior ocellus much posterior to midpoint between antennal bases and posterior edge of vertex; distance between posterior ocelli slightly less than or about equal to distance to nearest eye margin. Inner margin of inner hind tibial spurs serrate with about a dozen or more small teeth, outer margin with seven or eight larger teeth; outer spurs with about six, low, inconspicuous teeth on each margin. Median teeth of sixth tergite short and slender. Color- ation similar to that of female, teeth of sixth tergite red. Punctation similar to that of female, punctures of clypeus finer and close. Length 5 to 6 mm.
This species is found in much of the Pacific coast region, in the mountains and in the valleys west of the mountains. In the arid regions east of the Sierra Nevada it is replaced by another subspecies, described below. I have seen only a single specimen of timberlakei from Washington, and records for Oregon are few, but in northern and western California it is the most common species of the subgenus.
OREGON: Wild Horse Canyon, Andrews, 4270 feet elevation, June 5, 1927 (H.A. Scullen); Eagle Ridge, Klamath County, May 15, 1924 (C.L.Fox, Calif. Acad. Sci.) CALIFORNIA: Cobb Mountain, Lake County, May 7, 1936; Antioch, April 18, 21, and May 26; Mineral King, Tulare County, August 1, 1935 (all G.E. and R.M.Bo- hart); Yosemite, 3880 to 4000 feet elevation, May 31, 1938; El Portal, May 23, 1938; Tulomne County, 3500 feet, June 9, 1938; Bass Lake, Madera County, June 6, 1938 (all R.M.Bohart); Hastings Natural History Reservation, near Jamesburg, Santa Lucia Mountains, Monterey County, 2000 feet elevation, June 1, 1938 (C.D.Michener); Huntington Lake, Fresno County, 7000 feet elevation, July 4, 1919 (F.E.Blaisdell); Giant Forest, Tulare County, July 22, 1923 (C.L.Fox); Tamalpias, June 20, 1936, on Lotus glaber (P.H.Timberlake); Lake Arrowhead, San Bernardino Mountains, July 20, 1935 (M.Cazier); Idyllwild, Riverside County, June 25, 1928 (E.C.Van Dyke); Keen Camp, Riverside County, June 6 to 12, 1917 (E.P.Van Duzee); Big Pines Camp, July 12, 1927, on Phacelia heterophylla; Lone Pine Canyon, 4000 feet elevation, June 6, 1922, on Lotus scoparius; Cajon Valley, July 4, 1933, on Lotus scoparius; Swartout Valley, June 3, 1928, on Phacelia davidsonii and P. heferophylla; Sheep Creek, San Gabriel Mountains, June 3, 1928, on Lotus scoparius; Coffee Camp, June 8, 1925, on Lotus glaber, Tune 25, 1929, on Trifolium variegatum; Green Valley, June 9, 1933, on Lotus scoparius; Riverside, March 19 to May 24, on Lotus glaber and L. scoparius; the Gavilan, June 24, 1938, on Lotus scoparius; Puente Hills, May 11, 1930; Andreas Canyon, near Palm Springs, April 11, 1936, on EriodictXon cras- sifolium; Badger, June 26, 1929, on Lotus nevadensis (all P.H.Timberlake).