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Show 150 ME. E. E. AUSTEN ON NEW DIPTEEOUS INSECTS. [Jan. 17, Facial tubercle and oral margin pale orange, the remainder of the face and cheeks pale yellow, opalescent. Front clothed with short dark pile, tawny pollinose, anterior face of antenniferous projection shining; a smaller and fainter black spot in the median line posteriorly, near the apex of the angle formed by the eyes ; ocelligerous tubercle black, clothed with short and rather stout black hairs, which curve forwards. Antenna orange, short, third joint blunt. Sides of the thorax orange, dull, but becoming brassy below; two of the narrow leaden stripes are approximated in the median line in front, and do not reach more than halfway ; the other two stripes, which are slightly broader, are lateral in position, one on each side, and extend almost to the hinder margin ; besides these there is a faint indication of a fifth stripe, median in position, starting from between the ends of the median stripes, and running to the hind margin of the dorsum ; metanotum greenish bronze ; post-alar callosities orange, shining: the dorsum of the thorax in front and the anterior portion of the pleurae are thinly clothed with yellow pile, which becomes more orange near the base of the wings ; the dorsum near the transverse suture with short brown pile. Scutellum ochraceous, with yellow pile below, and dark brown pile round the margin. First segment of the abdomen yellowish ochraceous, tumid and pale yellow at the sides ; the remainder of the abdomen rufous ochraceous, with orange-ochraceous markings; on the second segment these markings consist of a narrow and ill-defined transverse band close to the hind margin, and of a crescent-shaped band on the posterior half of the segment, convex anteriorly, widely separated in the middle line, and tapering towards the posterior angles ; the third and following segments are marked by five continuous longitudinal stripes, of which that in the median line is very narrow and not sharply defined, while the intermediate ones are much the broadest and most sharply defined ; the stripes formed by the ground-colour on each side of the median line are slightly broader than the intermediate orange-ochraceous stripes, while those between the latter and the lateral stripes are much broader than any of the light-coloured stripes; on the fifth segment the stripes converge posteriorly. Genitalia small, concealed. Legs yellow, a band on the distal half of the posterior femora, not reaching to the tip, and the distal half of the posterior tibiae pale brown. Wings uniformly suffused with pale sienna colour; the auxiliary and first longitudinal veins, and the bases of the following veins as far as the fifth, pale orange : third longitudinal vein rather abruptly convex forwards above the distal half of the first posterior cell. Brazil, region of the Amazon (Bates): one specimen. This species is apparently closely allied to Baccha notata, Lw. ( Dipt. Amer. Septent., Cent. vii. 65), from Cuba, and belongs to the group of which Baccha livida, Schin. (Reise ' Novara,' 343), Baccha (Syrphus) flavipennis, Wied. (Auss. zw. Ins. ii. 123), and Baccha lineata, Macq. (Dipt. Exot. i. Suppl. 139, t. 20. fi<r. 5), are also members. |