Isomyia perisi James 1970

Isomyia perisi

MALE.—Head largely black. Gena, cheek groove, lower outer part of faciale, and lunule reddish brown, face and rest of faciale reddish yellow; middle of gena rather indefinitely biownish; pollen of parafrontals, parafacials, and occiput cinereous, that of faciale, parafacial, cheek groove, and gena concolorous with background; lunule with clearly evident yellowish pollen, visible from any angle, on more than its posterior half. Occiput with long yellow hairs medially, most conspicuous below glabrous area of upper occiput but also visible back of proboscis, other hairs, setulae, and bristles of head black. Frontals about 12, upper ones becoming size of larger setulae; setulae abundant on parafrontals and parafacials; lunule without setulae. Width of frons at narrowest little more than diameter of anterior ocellus, frontale completely obliterated at narrowest. Antennal scape and pedicel reddish brown, flagellum reddish yellow, brown above except at base. Arista reddish brown to brown, subbasal third yellow; rays brown. Measurements in micrometer units: head width, 310; width of frons at minimum, 8, at vertex, 30; distance between vibrissae, 62; vibrissa to oral margin, 45; oral margin to lower margin of lunule, 130; parafacial at antennal base, 20, at cheek groove, 32; width of gena, 70; eye height, 210; antennae separated by 10; length of pedicel, 20, of flagellum, 40.

Thorax blue-green with purplish reflections, especially laterally; pollen brownish gray, clearly evident from posterior view over most of mesonotum, scant on scutellum, lacking or scant on most pleural areas, most evident there on part of the stemopleuron; darker pollen resulting in a pair of narrow presutural vittae between acrostichal and dorsocentral rows; hairs, setulae, and bristles mostly black, some around anterior spiracle and posterior mesopleural fringe dark brown. Coverings of anterior spiracle brownish black, that of posterior black. Acrostichals, 2, 3, anterior presutural and postsutural much weaker than others; dorsocentrals, 2, 4; scutellars, 4 lateral, 1 or 2 discal; pteropleural, 1, surrounded by setulae as long as the bristle, some of them almost bristle-like; 1 accessory propleural, no accessory stigmatals.

Coxae and femora black, anterior pair with strong blue-green reflections, coxa anteriorly and femur posteriorly virtually blue-green, others with traces of such; tibiae and basitarsi reddish brown to brown, anterior pair palest; trochanters and tarsi beyond basitarsi black. Middle tibia without median ventral. Wing pale brown, almost hyaline; bend of M1 pronounced, forming approximately a 100° angle, but rounded at bend. Basicosta black; halteres reddish yellow; squamae wholly dark brown.

Abdomen bluish green. Pollen scant except on second sternum and inner half of ventral areas of second and third terga, where it is dense and cinereous. First abdominal tergum and posterior margins of second and third, also a broad median vitta dorsally on second and a narrow one on third, black, with purple reflections; ventral sides of first three terga with strong violet reflections, fourth less so; black areas of posterior margins of second and third much more broadly developed ventrally than dorsally. Fourth tergum well set (except on basal third) with discals, not arranged in rows. Second sternum with about eight pairs of bristles, but with no stronger apical pair, and with long yellowish hairs; bristles, setulae, and hairs of abdomen black, unless otherwise noted. Genitalia as in Figure 1d. Length, 13 mm.

FEMALE.—Frontale brownish black. Pollen of parafrontals and parafacials variable in color, usually brownish to yellowish brown, darker on parafrontals than on parafacials, sometimes mostly cinereous as in the male. Pale hairs of upper occiput not as long or as deep yellow as in male. Measurements in micrometer units: head width, 310; width of vertex, 90, of frons at base of antennae, 125, of frontale and parafrontal at anterior ocellus, 35 and 25, of same at antennal base 42 and 42, of parafacial at cheek groove, 30. Frons gradually broadening from anterior ocellus to base of antennae. Middle tibia with a strong ventral a little beyond middle. Discals of fourth tergum arranged mostly in a row just anterior to midline of tergum. Length, 13 mm (allotype: range, 12–13 mm).

HOLOTYPE.— , South India, Madras, Anamalai Hills, Kadamparai, 3,500 feet, May 1963; P. S. Nathan; USNM 70754.

ALLOTYPE.— same data as holotype.

PARATYPES.—5 , same data; 5 , same data but Anamalai Hills, Cinchona, May 1964; 1 , same data but Cinchona, September 1964.