|
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 probably the most common, most widely distributed, and most easily collected speeies of Synhalonia in California. It ranges northward to Washington and Idaho and east as far as Colorado, and it is much less common on the Colorado or Mohave Deserts than in the cismontane areas of California. It seems almost certain that Diadasia tricincta Provancher is a synonym of actuosa.
Female.—Black; small joints of tarsi ferruginous. Wings dusky hyaline, nervures fuscous, subcosta black. Pubescence moderately short, thin enough to reveal surface of mesonotum, pale ochreous and more whitish beneath. Abdomen with narrow band of appressed white hair at apex of tergites 2 to 4, the base of tergite 2 with thin, short, erect whitish hair, and hair on disk of tergites 3 to 5 black; apical band on tergite 5 white on each side and chocolate brown on middle third.
Head more transverse than usual, inner orbits of eyes parallel. Vertex only slightly impressed on each side. Lateral ocelli their own diameter from occipital margin and their distance apart from nearest eye. Clypeus finely rugoso-punctate, sometimes with a median ridge more or less developed. Frons and mesonotum opaque, obscurely punctured. Second submarginal cell small, quadrate, receiving recurrent nervure about one-sixth to one-half of its length before apex. Pygidial plate longer than wide at base and moderately wide at apex. Length about 11 mm, anterior wing 6.2 mm, width of abdomen 4.5-4.6 mm.
Male. Black, with small mark on middle of labrum and clypeal mark pale yellow. Clypeal mark widely separated from margin of eyes, reaching summit of clypeus, about as long as its dorsal width, but much wider below. Pubescence long, fine, erect, pale ochreous or whitish, not concealing surface of head or thorax. Hair of tergite 1 very long and pale, that of following segment moderately short, erect, and black beyond basal part of tergite 2. Antennae black as usual, but flagellum sometimes tinged with brown beneath.
Head much broader than long, inner orbits of eyes moderately divergent above. Vertex moderately impressed on each side, summit of eyes rather prominent. Lateral ocelli about their own diameter from occipital margin and slightly closer to margin of nearest eye than their distance apart. Oculoclypeal space moderately narrow. Antennae about reaching apex of tergite 1; joint 3 one-half as long as 4. Sculpture as in female, except that clypeus very shallowly and indistinctly punctured. Abdomen dullish, finely, closely, and rather roughly punctured, the punctures reaching, or almost reaching, apical margin on tergites 1 to 6, although finer on the apical depressions, Sternite 6 with a high, laminate keel on each side, with rounded outline in profile view and abruptly truncate at apex; disk on outer side of keels with a polished impression terminating in a rounded marginal lobe. Sternites 7 and 8 as figured. Parameral lobes of genital armature as wide at base as at apex, narrowed at middle, outer side of basal half with thin fine hair. Length 7.5-11 mm, anterior wing 6.75-8 mm.
|
