Baccha chalybea new species
A brassy black species with brownish hyaline wings and dark brown stigma. Related to Baccha cuthbertsoni CURRAN. Length 8.8 mm.
Male. Head: Vertex shining black with a single row of brownish black pile. The front is brassy black with a bit of yellowish grey pubescence at the junction point of the eyes. The front is somewhat swollen about the area of the frontal callus, its pile sparse and dark brown to black and restricted to the margins of the front. There may be a violet, linear band surrounding the antennal callus; the face is shining brownish black, or more seldom reddish brown, and there is considerable grey pollen along the sides of the face, especially toward the eye margin; a narrow, conspicuous, linear stripe of whitish pollen runs along the eye margin to about midway along the cheeks. The facial tubercle is moderate and wholly shining; the antenna is light reddish brown, the base of the third segment is a little more orange, its dorsal apex is a little more brown. The arista is light brownish yellow, rather strongly thickened at the base and darker apically. The arista has a row of moderately long, whitish hairs on the thickened part of the dorsomedial aspect, seen under the high power of the microscope. The pile of the occiput consists of a single row of long, pale yellow, flattened hairs; the upper portion of the eye encroaches on the occiput obliterating it in profile.
Thorax: The mesonotum is brightly shining brassy black with a suggestion of brown; scutellum concolorous; the pile of both is sparse, erect and light golden brown. There are a few very delicate, slightly longer, golden hairs on the margiu of the scutellum and its ventral fringe consists of about 9 quite long, delicate, light golden hairs. The mesonotum has inconspicuous collar of hairs anteriorly; although the anterior pile of the mesonotum is long, the collar of pile is not well differentiated. The pleuron is bright brassy with curved, reddish brown pile. Squama brown with reddish sepia border and fringe. Knob of halteres light yellow, the stalk brown at base.
Legs: The legs are light yellowish brown; the apical half of the hind femur, apical third of this tibia and the premedian, obscure annulus on this tibia sepia brown. Hind tarsus light brown, its basitarsus barely paler.
Wings: The wings are light brownish hyaline, the stigma dark brown, the third vein strongly curved and subsigmoid, the subapical crossvein sigmoid, the anal spuria virtually absent, the alula rather well developed.
Abdomen: The abdomen is of the petiolate type; the second segment is about 4 or 5 times as long as its basal width and 7 or 8 times as long as its narrowest width, and subcylindrical. The apex of the abdomen is between 3 and 4 times as wide as the middle of the second seg- ment. First segment shining black with the merest suggestion of a blue reflection in the middle and brassy in the corners. The second segment is brassy sepia black and shining with wide, opaque bands posteriorly, the third segment similarly colored with large, opaque triangles; the fourth segment similarly colored, opaque areas, if present, are more obscure; fifth segment and hypopygium concolorous. The pile of the abdomen is light reddish brown along the sides of the first and second segment, becoming darker reddish basally and laterally on the remaining segments and almost black posteriorly on the remaining segments.
Female. The female is similar to the male in most respects. The front is shining black, . without brassy reflections; on either side along the eye margins there is a hemicircular, grey, pollinose spot; the frontal pile and the single row of vertical pile is light yellowish. The mesonotal pile is short, sparse, curled, appressed and almost white. Pleural pile yellowish white, much appressed. Color of mesonotum and scutellum shining black, the ventral fringe has some 12 to 14 yellowish white hairs. The abdomen is shining black, the opaque triangle of the third segment more or less evanescent in the middle, the abdominal pile paler. The legs are similar to Baccha cuthbertsoni but the wings are much more hyaline.
Cape Prov.: Holotype male, allotype female and 2 paratype males, Hout Bay, Skoorsteenkop, Cape Peninsula, 22.1.1951, loc. no. 157. — Same locality, 2 paratype females, 2.2.1951, loc. no. 166. — Paratype, fernale, Bloukrans River, 20 miles ENE Plettenbergbaai, 11.1.1951, loc. no. 133 (BRINCK and RUDEBECK).
unless otherwise stated