OCR Text |
Show 1893.] ME. E. E. AUSTEN ON NEW DIPTEEOUS INSECTS. 149 triangle long, narrow, cinereous pollinose. Front in the 2 > except the posterior third, which is cinereous pollinose, pale shining yellow, with a blackish-brown dot in the centre line above the base of the antennae, from which a narrow brown median stripe runs back to the pollinose portion: ocelli remote from the vertex in both sexes. Antennas yellow, third joint rounded at the tip ; arista black. Occiput cinereous pollinose. The median cinereous pollinose stripe on the thorax is much narrower, and also somewhat longer, than the lateral ones, but all the stripes terminate at a considerable distance from the scutellum : front portion of the pleurae metallic yellow; pectus, posterior portion of the pleurae, and metanotum steely black. Scutellum yellow ; a narrow stripe along the anterior margin, tapering towards the sides, which it does not quite reach, black. First segment of the abdomen with a dark brown posterior border, the lateral protuberances with a tuft of yellow pile ; second segment with the anterior and posterior thirds (in the typical d rather more than the anterior third) dark brown, so that the yellow ground-colour is restricted to a band across the middle ; this may appear to be narrowly divided in the median line ; third and fourth segments with the hind margin, the median third of which is expanded (considerably so in the typical d ), a quadrate area occupying each posterior angle, a somewhat clavate mark projecting inwards and forwards from these, and a median narrow stripe dark brown ; in the typical $ the median stripe does not quite reach the anterior margin of the segment, while the " clavate " markings are narrower and less clavate than in the d : in a second d in the collection the median stripe is much broader, and also does not quite reach the anterior margin; on the fifth segment the markings are precisely similar, except that the brown posterior margin and the quadrate areas in the posterior angles are almost obsolete, and that (in the typical specimens at least) the median stripe reaches the anterior margin of the segment in both sexes : sixth segment yellow. Third longitudinal vein of the wings somewhat sinuate, convex forwards above the distal half of the first posterior cell; terminal portion of fourth vein bounding the first posterior cell only slightly oblique ; posterior cross-vein straight. Brazil, region of the Amazons (Bates) : three specimens. This species is distinguished by its size and markings from any other known to me. Group II. B A C C H A SILACEA, sp. n. (Plate V. fig. 13, d •) d . Length 10 m m . Thorax dull, clothed with dense pollen of pale sienna colour, with narrow leaden stripes ; a somewhat sharply defined median pyriform area on the pectus greenish bronze ; abdomen flattened, but little contracted basally, rufous ochraceous, with orange-ochraceous stripes front with an obtuse antenniferous projection, marked with a round black spot: alulce of full size. |