Extracted from: Timberlake P.H., (1969). A Contribution to the Systematics of North America Species of Synhalonia (Hymenoptera, Apoidea). University of California Publications in Entomology Volume 57|
This is a distinctive species, known as yet only from Texas. The male resembles speciosa in having sternites 7 and 8 more curiously modified than usual. The female has the hair of abdomen mainly black beyond the first tergite, and I might hazard the guess that aragalli may prove to be the light form of the species.
Male.óBlack; small joints of tarsi dark ferruginous; tibial spurs testaceous. Mandibles and antennae entirely dark. Labrum and clypeus pale yellow; clypeal mark almost reaching margin of eyes, much broader than high, obtusely emarginate on each side and broadly trun¨cate at summit. Pubescence ochreous, whitish on face and beneath, and moderately dense. Hair of tergite 1 whitish, long, and erect, that of remainder of abdomen mainly black, but having the long fine hairs from basal margin of apical depressions of segments whitish, and a light band more or less distinct at apex of tergite 6. Hair of venter entirely dark. Hair of legs whitish, but ferruginous on inner side of tarsi. Tegulae amber, infuscated at base. Wings subhyaline, nervures dark ferruginous, subcosta black.
Head much broader than long; inner orbits slightly divergent above. Vertex strongly im¨pressed on each side; lateral ocelli their own diameter from occipital margin and about twice as far from nearest eye. Proboscis rather short, galeae no longer than stipites. Antennae reaching apex of tergite 1; joint 3 on long side somewhat longer than wide and about one-fourth as long as joint 4. Oculoclypeal interval very narrow. Second submarginal cell receiv¨ing recurrent nervure about one-fourth to one-third of its length from apex. Legs normal; hind basitarsi strongly widened toward apex. Sternite 6 with distinct, slightly oblique im¨pression on each side, terminating in low, rounded marginal lobe; disk shining, with small, oval, smooth space in median line, between middle and apex; basal half with very short, erect hair, and apical margin with dense submarginal hair of moderate length on each side. Sternites 7 and 8 as figured; subgenital plate strongly bilobate at apex, the lobes curving downward and densely hairy on ventral side. Parameral lobes of genital armature straight, moderately long, broad at base, and only slightly and ovally expanded at apex, and clothed with rather pale fulvous hair except at apex. Length 11.5-13 mm, anterior wing 8.5-9 mm.
Female.óBlack, small joints of tarsi ferruginous, tibial spurs testaceous. Pubescence pale ochreous, paler beneath and on head, and rather short and moderately dense on mesonotum. Hair of tergite 1 moderately long and whitish, apical margin of segment broadly bare except on each side. Hair of following segments short, dense, and black, with some long, pale brownish hair overlying apical depressions on tergites 3 to 5. Hair of tergite 2 dense on each side and across the base, otherwise thin, appressed, and sometimes partly white to form evanescent arcuate band. Hair on extreme apical margin of tergites 3 and 4 sometimes partly whitish. Apical band on tergite 5 brownish and hair on each side of tergite 6 brown. Scopal hair of hind legs fulvous, and the dense hair on outer side of middle tibiae pale brown. Tegulae blackish on basal half, dark amber at apex. Wings moderately dusky; nervures dark ferruginous, subcosta black.
Head broader than long; inner orbits slightly divergent above. Vertex moderateley im¨pressed on each side; lateral ocelli their distance apart from nearest eye. Galeae of proboscis smooth and shining on inner border, otherwise minutely tessellate, dull, and with a few scattered, short, erect hairs. Clypeus with close, shallow punctures, separated by more or less broad, shining ridges, and sometimes with a median ridge triangularly widened at base. Mesoscutum moderately dullish, with dense punctures slightly more separated on posterior middle of disk; punctures of scutellum finer and denser. Pygidial plate about as long as wide at base and triangularly narrowed to rounded apex. Length 13 mm, anterior wing 9.5 mm, width of abdomen 5.3 mm.