| # Pest fruit flies of the world |

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

### Ensina sonchi (Linnaeus)

Musca sonchi Linnaeus, Ensina chrysanthemi Robineau-Desvoidy, Ensina doronici Robineau-Desvoidy, Ensina herbarum Robineau-Desvoidy, Ensina lacteipennis Hendel, Ensina linariae Robineau-Desvoidy, Ensina pratensis Robineau-Desvoidy, Ensina scorzonerae Robineau-Desvoidy, Tephritis asteris Haliday, Tephritis sonchi Fallén, Trypeta obsoleta Wiedemann

Sonchus fly.

Body. Body plump; a balanced mixture of black and yellow.

Head. Number of frontal bristles three pairs. Number of orbital bristles one pair. Anterior orbital bristle of male normal, unmodified. Posterior orbital bristles reclinate; acuminate. Ocellar bristles long, about as long as frontal bristles. Postocellar bristles present. With both inner and outer vertical bristles. Outer vertical, postvertical and postocellar bristles – outer vertical bristles acuminate, postvertical and postocellar bristles lanceolate and pale (postverticals minute or absent, assumed lanceolate). Postocular bristles lanceolate; normal. Genal bristle present. Head about as long as high. Male and female head width the same. Frontofacial angle about equal to a right angle and angular. Face concave; with distinct antennal grooves and carina; shorter than frons; with ventral part projected, or vertical; without dark marks. Parafacial spot absent. Frons and parafacial without small silvery markings. Fronto-orbital plate setulose. Frontal stripe non-setulose. Eye round, about as high or slightly higher than long. Antenna about as long as face. Scape, pedicel, and first flagellomere all relatively short. First flagellomere as long as face; rounded apically. Arista as long as first flagellomere; bare or with hairs distinctly shorter than greatest aristal width. Proboscis elongate, geniculate.

Thorax. Inner scapular bristle present and distinguishable from surrounding vestiture; pale. Outer scapular bristle present and distinguishable from surrounding vestiture; pale. 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 aligned with postsutural supra-alar bristles or slightly behind. Intra-alar bristle present, well developed, similar to postalar bristle. Intrapostalar bristles absent. Number of scutellar bristles two pairs. Apical scutellar bristles as long as basals or longer. Anterior notopleural bristle present. Posterior notopleural bristle(s) acuminate. Number of outstanding anepisternal bristles one. Katepisternal bristles present. Anepisternal bristles pale, yellowish. Long, erect setulae on laterotergite absent. Scutal setulae acuminate and pale. Scutellum sparsely setulose. Setulae on scutellum long, erect; unicolorous, acuminate. Transverse suture with the lateral branches wide apart. Complete sclerotized postcoxal metathoracic bridge absent or semimembranous. Scutum black; without a large dark central stripe which broadens basally. Postpronotal lobe entirely pale whitish or yellowish, or predominantly of the ground color (yellow). Posterior half of notopleuron pale whitish or yellowish, or same as ground color. Scutum dorsad of notopleuron with a pale whitish or yellowish stripe which extends from postpronotal lobe to posterior half of notopleuron. Discrete shiny black spots on scutum tiny, associated with alveoli. Median longitudinal black stripe on scutum absent. Number of pale whitish to yellow postsutural stripes zero. Area bordering scutoscutellar suture medially without dark brown spot, light colored. Discrete pale horizontal stripe along upper anepisternum present and distinct, extending from postpronotal lobe to wing base, or absent or indistinct. Distinct pale vertical anepisternal stripe extending to notopleuron, or absent. Katepisternite with pale yellowish or whitish spot present and distinct. Transverse suture without distinct stripe or spot. Katatergite with pale yellowish or whitish spot present and distinct. Anatergite with pale yellowish or whitish spot absent or indistinct. Subscutellum uniformly black. Mediotergite uniformly black. 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 with microtrichia covering entire wing. Cell bc microtrichia covering whole cell. Cell c microtrichia covering whole cell. Cell dm entirely microtrichose. Dense microtrichia at end of vein A1+CuA2 in male absent. Dominant wing pattern mostly hyaline. Crossbanded wing patterns with bands extensively fused, distorted, or greatly reduced. Wing pattern mostly yellowish. Dark longitudinal streaks through basal cells absent. Crossvein r-m hyaline, or covered by short, diffuse infuscation (faint). Crossvein dm-cu hyaline, or infuscated along entire length, but not reaching posterior margin of wing (faint). Crossveins r-m and dm-cu not both covered by a single crossband. Cell r2+3 apical to r-m with large hyaline area. Anal band absent, or not reaching nearly to wing margin. Cell r1 and r2+3 without darker spots within the pattern. Intercalary band absent. Subbasal crossband absent. Subbasal and discal crossbands not joined. Marginal hyaline area in cell r1 present and distinct. Ratio of width of apical band in cell r4+5 to length of r-m 0. Anterior apical band or costal band not extended to vein M. Posterior apical crossband absent. Discal band transverse, or oblique in anterobasal-posteroapical direction, or absent. Discal and apical crossbands not directly joined. Discal and subapical crossbands not joined. Discal and subapical bands not connected along vein R4+5. Subapical and anterior apical crossbands not joined, subapical crossband not reaching costa. Outstanding costal spine(s) at subcostal break absent. 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 absent; ventral setation absent or only present on node or close thereafter. 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; ratio of width to cell cup width 1–1.2. 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; as long as 5th. Abdominal setulae acuminate and dark. Abdominal microtomentum uniform. Abdominal sternite 5 of male less than 2x wider than long, not longer than wide. Posterior margin of sternite 5 of male with deep V-shaped posterior concavity. Abdominal tergites 3–5 predominantly yellow to orange brown. Abdominal tergites without medial dark stripe; not brown with medial T-shaped yellow mark; 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 rounded or oval, including the short, undifferentiated outer surstyli; lateral view with outer surstyli a continuation of the epandrium.

Female terminalia. Syntergosternite 7 straight; shorter than preabdomen; base without a laterally projecting flap; conical, or flattened. Ratio of syntergosternite 7 to abdominal tergite 5 3. Dorsobasal scales of eversible membrane about as large as other scales (?). Aculeus tip fused to main part of aculeus, not movable.

Miscellaneous. Male attractant: none known.

Palearctic, Afrotropical, Oriental, Australasian-Oceanian. Britain & Scandinavia S to North Africa, E to Japan; introduced Ethiopia, Taiwan, Philippines, Hawaii.

Tephritinae. Noeetini.

Illustrations. • Head (dorsal, lateral), thorax (dorsal), wing, female terminalia.

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.

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: 2nd April 2019. delta-intkey.com’.

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