OCR Text |
Show 1893.] ME. E. E. AUSTEN ON NEW DIPTEEOUS INSECTS. 153 base, and with the band across the middle about twice as broad third segment with a distinct narrow ochreous band across the base, widest in the middle and notched in the median line, tapering towards the sides (in the second specimen in the collection this band is merely represented by a faint line, but the specimen may have been captured very soon after it emerged), and with the main transverse band much broader ; fourth segment with the " lunate " marks represented by two stripes running straight from the front to the hind margin ; each of these sends off a narrow oblique mark from near its base towards the lateral margin, as do the corresponding marks in the 2 > and from its extreme base a narrow line runs to the lateral margin, along the base of the segment; fifth segment with a straight stripe running from the front to the hind margin on each side of the median line, and connected together posteriorly, but apparently with no trace of the small basal triangles : the legs are paler yellow, but the brown markings on the posterior pair and the posterior tarsi just as in the $ . The antennce are orange, short, the third joint rounded, and the second and third joints and the tip of the first narrowly dark brown above ; the arista dark brown; the shining black spot above the antennae narrower than in the $ ; the front is clothed with short dark pile. The alulas and the shape of the abdomen as in the 2 ; genitalia ochraceous. Brazil, Villa Nova and Santarem (Bates) : two specimens. BACCHA PLAVENS, sp. n. (Plate V. fig. 10, £ .) 2 • Length 12^ m m. Yellow, nearly bare ; dorsum of the thorax, except the sides, shining orange-rufous, ivith two abbreviated pale yellow stripes, which clothed with shimmering ivhitish pollen : abdomen deep chrome-yellow, with narrow shining brown transverse bands and lineate markings broad, fiat, not contracted basally, but expanding regularly to the of the fourth segment. Legs whollg yellow. Wings with an ochraceous tinge, strongest towards the anterior margin : alulce rudimentary. Face and cheeks pale yellow, shining, except the facial tubercle, which is dull. Front somewhat deeper yellow, dull, the posterior fifth dark olivaceous ; the slight antenniferous projection shining, pale yellow on the sides; a conspicuous shining black dot above the base of the antennae ; above this is a small brown blotch, from which a faint rufous median stripe runs back to the vertex. First two joints of the antennce ochreous; the third is missing. The yellowish shimmering, pollinose stripes of the dorsum of the thorax only extend about two-thirds of its length, and divide the orange-rufous area into a median and two lateral stripes, which are all of equal breadth and coalesce posteriorly; the sides of the dorsum, pleurae, pectus, aud metanotum metallic yellow: scutellum dull, tawny ochraceous, orange-ochraceous at the base. Abdomen : first segment pale yellow, shining, with a narrow faint brownish band occupying the median two-fourths of the hind border; second segment with a straight brown transverse band occupying about the |