Isomyia aurifacies James 1970

Isomyia aurifacies

FEMALE.—Parafrontals, ocellar triangle, and occiput, black; frontale brownish black; parafacials and cheek groove reddish brown, a black area occupying a considerable part of lower parafacial; gena reddish yellow, lunule and face more clearly yellow. Occipital orbits, parafrontals, parafacials, facialia, genae, lunule, and upper facial carina with golden yellow pollen, almost uniform but somewhat deeper in color on parafacials; pollen of face and occiput other than orbits yellow to pale yellow; lunule entirely pollinose. Bristles and hairs of head black except those of occiput, which are pale yellow above to mixed yellow and golden below. Setulae of parafacials in about three irregular rows. Frons gradually widening from vertex to antennal base; frontale widest at two-fifths distance from vertex to antennal bases. Antennae orange, flagellum somewhat brownish externally above; setulae black; arista orange, becoming brown at apex, rays mostly brown. Measurements in micrometer units: head width, 310; width of vertex, 90, of frons at base of antennae, 120, of frontale at maximum, 50, of parafrontal at same place, 26, of frontale and parafrontal at antennal base, 37 and 42; distance between vibrissae, 67; vibrissa to oral margin, 30; oral margin to lower margin of lunule, 105; parafacial at cheek groove, 29; width of gena, 48; eye height, 195; antennae separated by 9; length of pedicel, 18, of flagellum, 40.

Thorax green, scutellum more blue-green, with blue to purplish reflections varying with light incidence; mesonotum lightly but evenly cinereous pollinose, pollen visible best as viewed from behind, most noticeable along anterior margin of mesonotum; pollen of pleura scant except on lower part of sternopleuron. Posterior fringe of mesopleuron and softer hairs of pteropleuron brownish black, otherwise bristles, setulae, and hairs of thorax black. Distinct narrow vittae between acrostichal and dorsocentral rows from anterior margin of mesonotum to about two-fifths way between suture and scutellum, also postsutural vittae between dorsocentral and intra-alar rows and a triangular area behind posthumerals, devoid of setulae. Mesopleural pile only moderately long and dense. Posterior declivity with some black setulae. Coverings of anterior and posterior spiracles blackish brown. Acrostichals, 1, 2; dorsocentrals, 2, 4; humerals, 4; pteropleural, 1 plus 1 accessory; scutellars, 4 lateral, 2 discal; 1 accessory propleural and 1 accessory stigmatal.

Coxae and femora largely black; front coxa anteriorly, middle coxa in large part, front femur posteriorly on basal two-thirds, middle femur posteroventrally on basal half, and a ventral area at base of hind femur metallic green. Tibiae and basitarsi reddish yellow, front basitarsus above and other tarsomeres becoming brownish black. Middle tibia with strong ventral at three-fifths length. Wing yellowish, veins golden, more brownish toward base on lower surface; basicosta black; M1 broadly rounded at bend but bent at almost a right angle, strongly concave beyond bend; squamae uniformly brown.

Abdomen blue-green; first tergum largely with purplish reflections, especially ventrally; second to fourth terga with black posterior margins, broader ventrally than dorsally, and with a rather indistinct median vitta. Pale pollen cinereous, scant dorsally, visible at an angle at sides of second and third terga, much more prominent ventrally, a dense spot on first under squamae, otherwise densest toward midventral margins of first to fourth terga; second sternum with dense cinereous pollen. Hairs, bristles, and setulae mostly black; second sternum basally with brownish yellow hairs, otherwise with black setulae and about five pairs of black bristles; an irregular discal row at about one-third of fourth tergum dorsally. Length, 12 mm.

MALE.—Unknown.

HOLOTYPE.— , India, Assam, 10 miles north of Tinsukia, 11 April 1944, D. E. Hardy; USNM 70753.