Pest Fruit Flies of the World

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L.E. Carroll, I.M. White, A. Freidberg, A.L. Norrbom, M.J. Dallwitz, and F.C. Thompson

Dirioxa pornia (Walker)

Trypeta pornia Walker, Rioxa confusa Hardy, Trypeta musae Froggatt

Island fruit fly, Boatman fly, South Sea fly.

Body. Body plump; predominantly yellow.

Head. Number of frontal bristles two pairs. Number of orbital bristles two pairs. Anterior orbital bristle of male normal, unmodified. Posterior orbital bristles reclinate; acuminate. Ocellar bristles short, distinctly shorter than frontal bristles. Postocellar bristles present. With both inner and outer vertical bristles. Outer vertical, postvertical and postocellar bristles all acuminate. Postocular bristles acuminate; normal. Genal bristle present. Head higher than long. Male and female head width the same. Frontofacial angle about equal to a right angle and angular, or much greater than a right angle and rounded. Face concave, or flat, or undulating, convex above, concave below; with transverse sulcus, or with distinct antennal grooves and carina, or without transverse sulcus, antennal grooves, or carina; shorter than frons; vertical; without dark marks. Parafacial spot absent. Frons and parafacial without small silvery markings. Fronto-orbital plate setulose. Frontal stripe setulose. Eye round, about as high or slightly higher than long. Antenna considerably shorter than face. Scape, pedicel, and first flagellomere all relatively short. First flagellomere shorter than face; rounded apically. Arista longer than first flagellomere; plumose, with hairs at least half as long as first flagellomere width; hairs dorsal only, or both dorsal and ventral (ventral hairs sparse). Proboscis short, capitate.

Thorax. Inner scapular bristle present and distinguishable from surrounding vestiture; dark. Outer scapular bristle present and distinguishable from surrounding vestiture; dark. Postpronotal bristle present. Presutural dorsocentral bristle absent. Presutural supra-alar bristle present. Postsutural supra-alar bristle present. Acrostichal bristle present. Postsutural dorsocentral bristle present; bristles about midway between postsutural supra-alar and post-alar bristles. Intra-alar bristle present, well developed, similar to postalar bristle. Intrapostalar bristles present (range 2–3). Number of scutellar bristles three pairs. Apical scutellar bristles as long as basals or longer, or 50%-90% as long as basals. Anterior notopleural bristle present. Posterior notopleural bristle(s) acuminate. Number of outstanding anepisternal bristles two. Katepisternal bristles present. Anepisternal bristles dark, brown to black. Long, erect setulae on laterotergite absent. Scutal setulae acuminate and dark, or acuminate and pale. Scutellum non-setulose. Transverse suture with the lateral branches wide apart. Complete sclerotized postcoxal metathoracic bridge absent or semimembranous. Scutum yellowish, or orange-brown; without a large dark central stripe which broadens basally. Postpronotal lobe predominantly of the ground color. Posterior half of notopleuron same as ground color. Scutum dorsad of notopleuron of the ground color, not whitish or yellowish. Dark lyre-like pattern on scutum absent. Discrete shiny black spots on scutum absent. Median longitudinal black stripe on scutum absent. Number of pale whitish to yellow postsutural stripes zero. Scutum without blackish dorsocentral stripe. Area bordering scutoscutellar suture medially without dark brown spot, light colored. Discrete pale horizontal stripe along upper anepisternum absent or indistinct. Distinct pale vertical anepisternal stripe absent. Katepisternite with pale yellowish or whitish spot absent or indistinct. Transverse suture without distinct stripe or spot. Katatergite with pale yellowish or whitish spot absent or indistinct. Anatergite with pale yellowish or whitish spot absent or indistinct. Subscutellum uniformly yellowish to pale orange-brown (yellow), or yellowish to orange-brown medially, with distinct dark spots laterally. Mediotergite uniformly yellowish to orange-brown, or uniformly brown, or yellowish to orange-brown medially, with distinct dark spots laterally. Scutum entirely microtrichose, microtrichia evenly distributed, or at most with small presutural, medial bare area. Dorsum of scutellum flat or slightly convex, not swollen. Scutellum normal; without a dark and pale pattern (at most a narrow dark basal line); with no isolated dark spots; without black mark; without mark.

Legs. Femora slender. Fore femur with regular bristles; without ventral spines; with 1 to 3 posterodorsal and 1 posteroventral rows of bristles only. Mid femur and hind femur without spine-like bristles. Middle leg of male without feathering. Femora all entirely of one color; dark mark on fore femur 0% of length of femur; dark mark on middle femur 0% of length of femur; dark mark on hind femur 0% of length of femur.

Wings. Wing partly bare, or with microtrichia covering entire wing. Cell bc microtrichia absent, or present in apical area only. Cell dm entirely microtrichose. Dense microtrichia at end of vein A1+CuA2 in male absent. Dominant wing pattern cross-banded, or mostly dark. Crossbanded wing patterns with bands extensively fused, distorted, or greatly reduced. Wing pattern mostly brownish. Dark longitudinal streaks through basal cells absent. Costal band colored from Sc to beyond R4+5. Crossvein r-m covered by a major crossband. Crossvein dm-cu covered by a major crossband which reaches posterior margin of wing. Anal band absent, or not reaching nearly to wing margin. Cell r1 and r2+3 without darker spots within the pattern. Subbasal crossband absent. Marginal hyaline area in cell r1 present and distinct. Anterior apical crossband contiguous with costa over entire length, without marginal hyaline band or spots apically in cells r1 and r2+3. Anterior apical band or costal band extended to vein M. Posterior apical crossband present; fused to subapical band, or fused to anterior apical band. Discal and apical crossbands directly joined. Discal and subapical crossbands joined along anterior wing margin or along vein R4+5. Subapical and anterior apical crossbands joined. Outstanding costal spine(s) at subcostal break present. Ratio of length of costal section 3 to costal section 4 0.5. Ratio of pterostigmal length to width 3. Vein R1 dorsal setation without bare section opposite end of vein Sc. Vein Rs dorsal setation non-setulose. Vein R2+3 generally straight. Anteriorly-directed accessory vein emerging from R2+3 absent. Vein R4+5 dorsal setation sparse over both sections, or dense over at least proximal section; ventral setation present. Distance between crossvein r-m and costa longer than r-m. R-m crossvein on cell dm at or near distal third of cell dm. Cell bm narrow, triangular; ratio of length to width 4–4.5; ratio of width to cell cup width 0.75–0.8. Vein M distally straight. Cell dm widens apically gradually from base. Posterodistal corner of cell dm approximately a right angle. Cell cup extension or lobe present, vein CuA2 abruptly bent; shorter than vein A1+CuA2; triangular.

Abdomen. Abdomen ovate or parallel sided. Abdominal tergites separate. Abdomen in lateral view flatter, more flexible. Abdominal tergite 1 broader at apex than at base; without a prominent hump laterally. Pecten of dark bristles on tergite 3 of male absent. Tergal glands on tergite 5 absent. Abdominal tergite 5 normal. 6th tergite of female exposed; shorter than 5th, or as long as 5th. Abdominal setulae acuminate and dark. Abdominal microtomentum absent. Posterior margin of sternite 5 of male with shallow posterior concavity. Abdominal tergites 3–5 predominantly yellow to orange brown (fuscous laterally). Abdominal tergites without medial dark stripe; not brown with medial T-shaped yellow mark; with broadly contiguous dark areas on lateral margins of T3-T5 (T3-T5 contiguous fuscous laterally, or T3 separate), or with separate dark areas on anterolateral margins of T3-T5, or without isolated dark areas on lateral margins of T3-T5; with dark brown transverse bands which may be interrupted medially.

Male terminalia. Epandrium in posterior view with long outer surstyli, which are more than half as long as epandrium.

Female terminalia. Syntergosternite 7 straight; shorter than preabdomen; base without a laterally projecting flap; flattened. Ratio of syntergosternite 7 to abdominal tergite 5 2–3. Dorsobasal scales of eversible membrane about as large as other scales (?). Aculeus shaft parallel-sided except extreme base. Aculeus tip blunt; not fused to main part of aculeus, movable; 0% serrated; not serrate. Three sclerotized spermathecae.

Miscellaneous. Male attractant: none known.

Australasian-Oceanian. Australia (n. Qld. to e. cent. NSW), New Caledonia; records from New Zealand, Vanuatu, American Samoa, Fiji & Society Islands erroneous, based on interceptions.

Phytalmiinae. Acanthonevrini.

Illustrations. • Habitus female (dorsal), wing. • Wing. • Female terminalia. Dirioxa pornia.


Cite this publication as: ‘L.E. Carroll, I.M. White, A. Freidberg, A.L. Norrbom, M.J. Dallwitz, and F.C. Thompson. 2002 onwards. Pest fruit flies of the world. Version: 8th December 2006. http://delta-intkey.com’.

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