This species is most closely related to Andrena nemophilae. The females of sagittagalea are larger in size (wing length of 5.7 mm or more) and have slightly expanded hind tibiae with greatly spreading scopal hairs. The females of nemophilae are similar (wing lengths of 5.7 mm or less) and have considerably expanded hind tibiae (approaching the condition found in Scaphandrena) with scopal hairs which spread little, thus hairs are oriented in the same direcrion. The males of sagittagalea differ from nemophilae males by their terminalia, normal (for Andrena males) mandibles and almost entirely unshagreened clypei. The males of nemophilae have very long and greatly bent mandibles and shagreened clypei; sometimes the apical part of the clypeus lacks shagreeneing. This clypeal character generally distinguishes the females as well, the females of nemophilae having a more shagreened clypeus than those of sagittagalea, but there is some overlap in this feature.
Female. Differs from Andrena nemophilae in the following respects.
Measurements and ratios. length, 8.0 mm; width of mesothorax, 2.6 mm; wing length from tegula, 5.9 mm; facial length to width, 0.92; foveal length to width, 3.00.
Integumental color. flagellum orange-brown below.
Structure. Scape slightly longer than flagellar segments 1-4; flagellar segment 1 nearly as long as segments 2-4. Inner eye margins parallel below. Apex of mandible broadly rounded. Galea very shiny, with minute reticular shagreening. Maxillary palpus with segments in ratio of about 1.3 : 1.8 : 1.1 : 1.1 : 1.0 : 1.0; segment 6 only slightly flattened; palpus exceeding galea by about one palpal segment. Labial process half as wide as entire labrum; apex deeply emarginate. Clypeus with shagreening becoming very weak apicomedially, punctures absent on small apicomedial area, punctures otherwise close, obscured by shagreening basally. Supraclypeal area sculptured like base of clypeus, punctures partly obscured by reticular shagreening. Vertex extending past lateral ocellus by one ocellar width. Facial fovea dorsally as wide as eye, fovea narrowed below.
Pronotum with weak humeral angle, posterodorsal margin of pronotum flattened, laterally margin rather abruptly rounded to posterior pronotal lobe, pronotum in front of posterior pronotal lobe slightly flattened, humeral angle without a carina, pit in front of posterior pronotal lobe small, indistinct, suture extending from pit as in nemophilae. Parapsidal line of mesoscutum three-fourths width of tegula. Middle basitarsus only weakly expanded, four times as long as broad. Hind tibia slightly expanded, little wider than basitarsus. Wing with pterostigma half again as wide as prestigma, first m-cu vein ending near center of second submarginal cell.
Pygidial plate with apical margin upturned, center slightly but abruptly raised.
Vesiture. Foveal hairs white; sternal hairs, except subapical fimbria, simple; trochanteral flocculus weakly developed; tibial scopal hairs greatly spreading.
Male. Differ from Andrena nemophilae in the following respects.
Measurements and ratios. Length, 7.9mm; width of mesothorax, 2.1mm; wing length from tegula, 5.5 mm; facial length to width, .81; flagellar segment 1 to segment 2, 2.40.
Integumental color. Parocular area dark; flagellum orange-brown below; terga with braod amber apices.
Structure. Antenna reaching scutellum; flagellar segment 1 slightly longer than segments 2 and 3 together. Eye three and one-third times as long as broad in anterior view, inner eye margins parallel below. Mandible shorter, less bent than in nemophilae, subapical tooth pointed. Galea sculptured as in female. Maxillary palpus with segments in ratio of about 1.3 : 1.7 : 1.1 : 1.1 : 1.0 : 1.1; palpus otherwise as in female. Labial palpus with segments in ratio of about 2.4 : 1.2 : 1.0 : 1.4; palpus otherwise as in female. Labrum about three and one-half times as wide as long; process two-thirds as long and three-fourths as wide as entire labrum, expanded at base. Clypeus only slightly protruding beyond lower margin of eye in lateral view; clypeus very shiny, shagreening absent or very weak; punctures as in female but less obscured by shagreening. Supraclypeal area more heavily shagreened than clypeus. Vertex extending past lateral ocellus by one and one-half ocellar diameters.
Carina extending from humeral angle not sharp; pronotum in front of posterior pronotal lobe shiny, flattened, not deeply excavated. Center of mesoscutum shiny, with weak shagreening, punctures distinct; parapsidal line two thirds width of tegula. Scutellar surface in center very shiny, shagreening absent, otherwise scutellum sculptured like sides of mesoscutum. Propodeum with shagreening coarser on enclosure than on surrounding area. Posterior hind tibial spur longer than anterior spur. Wings as in female.
Apex of sternum 6 not emarginate.
Sternum 7 with many branched setae. Sternum 8 slightly different in shape; sete on apicomedial part stout, simple. Gonocoxite different in shape than in nemophilae; dorsal lobes short, broad. Penis valve different in shape.
Vestiture. Hairs white except some amber hairs on mandible. Apical abdominal fasciae as in female except fasciae weaker, fascia present but very weak on tergum 1.
Type material. All are from Texas. Holotype female (KU), 26 Female Female paratypes (KU, INHS), Lincoln, April 13, 1953, L. D. Beamer, on Phacelia; allotype Female (KU), 28 Female, 1 male paratypes (KU, INHS), same data except R. H. Beamer. Paratypes (KU, ANSP, INHS, USNM, NU): 37 female female, same data as allotype except no flower; 5 female female, Luling, March 30, 1951, R.H. Beamer, on Salix; 1 female, 1 male, same data except C.D. Michener; 5 female female, Lincoln (6 mi. E.), April 14, 1953, L. D. Beamer, on Phacelia; 1 female, Bastrop State Park, Bastrop Co., April 15, 1953, L.D. Beamur; 1 female, Palmetto State Park, Gonzales Co., April 5, 1954, on blue flower; 8 female female, 5 male, Calvert, 4-5-07, C. R. Jones; 1 female, Lee Co., April 18; 1 male, Lee Co., April 12, 1906; 1 female, Lee Co., April 17, 1906; remaining paratypes are from Fedor, Lee Co.; 1 female, 1 male, no date, G. Birkman; 1 female, 2 male male, April 10, 1905; 1 female, April 19, 1901; 1 female, April 13; 1 female, April 14; 1 female, april 14, 1901; 1 female, May 7, 1901; 1 male, April 19, 1899; 1 male, April ?17; 3 male male, April 10; 1 male, April 7, 1905; 1 male, April 1905.
The descriptions are based upon the holtype female and allotype male except for the male mouthparts. The specific name refers to the arrow-shaped galea. Previously Vireck applied two different manuscript names to this species
Remarks. This species is represented only by the type specimens from a few localities in central Texas. A preference for flowers of the genus Phacelia (Hydrophyllaceae) is indicated sience sixty females were collected on Phacelia and only one on another flower, Salix. Andrena sagittagalea has been collected between March 30 and May 7. A female bee from Calvert carried a saproglyphid mite (Vidia sp., det. R. C. Funk).
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