Pest Fruit Flies of the World
Dacus diversus Coquillett, Dacus citronellae Kapoor & Katiyar, Dacus quadrifidus Hendel
Body. Body a balanced mixture of black and yellow.
Head. Number of frontal bristles two pairs. Number of orbital bristles one pair. Anterior orbital bristle of male normal, unmodified. Posterior orbital bristles reclinate; acuminate. Ocellar bristles absent or minute, like setulae. Postocellar bristles present (pale), or absent. With both inner and outer vertical bristles. Outer vertical, postvertical and postocellar bristles all acuminate. Postocular bristles acuminate; reduced in number and size, hardly detectable in 25x (pale). Genal bristle present. Head higher than long. Male and female head width the same. Frontofacial angle about equal to a right angle and angular. Face concave, or undulating, convex above, concave below; without transverse sulcus, antennal grooves, or carina; shorter than frons; vertical; without dark marks (male), or bicolorous, with ventral part black (females, occasionally males; confined to concavity on lower third of face (Bezzi)). 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 longer than face. Scape, pedicel, and first flagellomere scape and pedicel short, first flagellomere elongate. First flagellomere as long as face; rounded apically. Arista longer than first flagellomere; bare or with hairs distinctly shorter than greatest aristal width. 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 absent. Presutural dorsocentral bristle absent. Presutural supra-alar bristle absent. Postsutural supra-alar bristle present. Acrostichal bristle present. Postsutural dorsocentral bristle absent. Intra-alar bristle present, well developed, similar to postalar bristle. Intrapostalar bristles absent. Number of scutellar bristles one pair, or two pairs (basal pair weak). The single pair of scutellar bristles apical. Apical scutellar bristles as long as basals or longer (longer). Anterior notopleural bristle present. Posterior notopleural bristle(s) acuminate. Number of outstanding anepisternal bristles one. Katepisternal bristles absent. Anepisternal bristles dark, brown to black. Long, erect setulae on laterotergite absent. Scutal setulae acuminate and pale. Scutellum densely setulose. Setulae on scutellum short, decumbent; unicolorous, acuminate. Transverse suture with the lateral branches wide apart. Complete sclerotized postcoxal metathoracic bridge present. Scutum black; without a large dark central stripe which broadens basally. Postpronotal lobe entirely pale whitish or yellowish; concolorous with lateral postsutural stripe. Posterior half of notopleuron pale whitish or yellowish. 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 two (lateral) (medial stripe sometimes absent in female), or three. Pale medial postsutural stripe of scutum linear. Lateral postsutural stripes of scutum extending to intra-alar bristles or beyond. Area bordering scutoscutellar suture medially without dark brown spot, light colored, or without dark brown spot, brown. Distinct pale vertical anepisternal stripe extending halfway between posterior half of notopleuron and anterior notopleural bristle, or extending to anterior notopleural bristle. Katepisternite with pale yellowish or whitish spot present and distinct. Transverse suture with pale transverse stripe extending medially from notopleuron anterior to suture, or covered by extension of postsutural lateral stripe. Katatergite with pale yellowish or whitish spot present and distinct. Anatergite with pale yellowish or whitish spot present and distinct. Subscutellum uniformly brown, or uniformly black. Mediotergite uniformly brown, or uniformly black, or yellowish to orange-brown medially, with distinct dark spots laterally. Scutum microtrichia in discrete pattern due to bare areas or completely absent (2 central broad microtrichose stripes delimited by medial & lateral narrow non- microtrichose stripes). 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 at least one femur markedly darker in apical part than in basal part; dark mark on fore femur 0–30% of length of femur (0(male)/0.3(female)); dark mark on middle femur 30–70% of length of femur (0.3(male)/0.4–0.7(female)); dark mark on hind femur 0–30% of length of femur (0(male)/0.3(female)).
Wings. Wing partly bare. Cell bc microtrichia absent. Cell c microtrichia present in apical area. Cell dm bare on less than basal one-third. Dense microtrichia at end of vein A1+CuA2 in male absent. Dominant wing pattern costal-banded. Wing pattern mostly brownish. Dark longitudinal streaks through basal cells absent. Costal band colored from Sc to beyond R4+5. Apex of costal band not distinctly expanded. Costal band not extending below R2+3; all one color. Crossvein r-m hyaline. Crossvein dm-cu infuscated at posterior end (indistinct). 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 present, reaching nearly to wing margin along cell cup extension. Cell r1 and r2+3 without darker spots within the pattern. Intercalary band absent. Subbasal crossband absent. Marginal hyaline area in cell r1 absent or indistinct. Ratio of width of apical band in cell r4+5 to length of r-m 0.4–0.5. Anterior apical band or costal band not extended to vein M. Posterior apical crossband absent. Outstanding costal spine(s) at subcostal break absent. Ratio of length of costal section 3 to costal section 4 1. Ratio of pterostigmal length to width 7. 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 dense over at least proximal section; ventral setation present. Distance between crossvein r-m and costa shorter than r-m. R-m crossvein on cell dm at or near distal third of cell dm. Cell bm broad, parallel-sided; ratio of length to width 2; ratio of width to cell cup width 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; longer than vein A1+CuA2; with parallel margins.
Abdomen. Abdomen ovate or parallel sided. Abdominal tergites separate. Abdomen in lateral view arched, dome-like, rather rigid. 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 present. Abdominal tergite 5 normal. 6th tergite of female normally concealed; shorter than 5th. Abdominal setulae acuminate and pale. Abdominal microtomentum uniform, or absent. Abdominal sternite 5 of male broad, at least 2x wider than long (3x as wide as long). Posterior margin of sternite 5 of male with shallow posterior concavity. Abdominal tergites 3–5 predominantly yellow to orange brown. Abdominal tergites with medial dark stripe on T3-T5 and a transverse dark line on T3 (also has transverse bands), or with medial dark stripe, usually on T3-T5, or 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 with long outer surstyli, which are more than half as long as epandrium; lateral view with outer surstyli distinctly narrower than epandrium, clearly differentiated. Posterior lobe of surstylus short or absent.
Female terminalia. Syntergosternite 7 straight; shorter than preabdomen; 1.82 mm; base without a laterally projecting flap; flattened. Ratio of syntergosternite 7 to abdominal tergite 5 3 (?; slightly longer than A4+A5, Coquillett 1904). Dorsobasal scales of eversible membrane about as large as other scales (?). Aculeus length 1.17 mm. Aculeus tip fused to main part of aculeus, not movable; 0% serrated; not serrate. Two sclerotized spermathecae. Spermathecae tight-set coils.
Miscellaneous. Male attractant: isoeugenol ((Ripley & Hepburn)).
Oriental. Pakistan, India, Nepal, Sri Lanka, China (Sichuan, Yunnan), Thailand.
Illustrations. • Habitus female (dorsal), wing, female terminalia.
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’.