Orthonevra bellula ( Williston, 1882 )

Miranda, Gil F. G., Soares, Matheus M. M. & Thompson, Christian, 2024, The Neotropical Orthonevra Macquart, 1829 (Diptera: Syrphidae), Zootaxa 5484 (1), pp. 1-78 : 16-17

Orthonevra bellula ( Williston, 1882)

Chrysogaster bellulus Williston 1882: 304 . Type-locality: USA, California (LT male USNM here designated).

Chrysogaster bellula . Williston 1887a: 36, figs (head, wing) (description), 1891: 7 ( Mexico, Durango, Michocán, difference from nitida ); Aldrich 1905: 348 (catalog citation); Kertész 1910: 31 (catalog citation); Fluke 1957: 49 (catalog citation).

Chrysogaster (Orthonevra) bellula . Sedman 1964: 170, figs (eye, mesonotum, wing) (key reference, descriptive note, distribution).

Orthonevra bellula . Thompson et al. 1976: 91 (catalog citation).

Figs 5 and 6

Differential diagnosis. Pile of the face long and scale-like ( Fig. 5f ); eye with sub-anterior vitta straight dorsally and sinuous ventrally, and middle straight vitta and complete fascia; scutum with 4 long more matte and darker vittae, without any other shorter vittate maculae laterally ( Fig. 5b, e ); wing with narrow faint dark vitta from end of R2+3 to R4+5, and on anterior half of M1; male surstyli symmetrical, with dorsal short triangular lobe and long ventral lobe.

Length. Body 5.73–6.41mm (n=3), wing 4.32–4.82mm (n=3); female 5.83–6.89mm (n=3), wing 4.53–5.44mm (n=3).

Distribution. USA (Washington to Idaho and South Dakota, south to California).

Comments. The lack of a lateral dark vittate macula on the scutum is unique among the species studied. The female genitalia are illustrated for the first time ( Fig. 6 ). No map was generated for this species since it is restricted to the Nearctic region.

Material examined: USA. California, Vacaville , 1.x.1950, A.T. McClay (2 males CNC, CNC _ Diptera 91362– 3); Shasta, Shingleton, 2.vi.1941, P.D. Hurd (1 female CNC, CNC _ Diptera 91364); Walnut crk, ??.iii.????,? (1 male CNC, CNC _ Diptera 91359) ; Oregon, Medford , 5.ix.1950, A.T. McClay (1 female CNC, CNC _ Diptera 91366) ; Utah, Devil’s Kitchen , 14.viii.1943, G.F. Knowlton & D.R. Maddock (2 males CNC, CNC _ Diptera 91358, …91361); Moab, 8.v.1941, G.F. Knowlton & F.C. Harmston (1 female CNC, CNC _ Diptera 91365); Promontory, 5.x.1942, G.F. Knowlton & W.E. Peay (1 male CNC, CNC _ Diptera 91360) .

Figures

FIGURE 5. Orthonevra bellula (Williston, 1882). a–c. Female: a. Habitus dorsal. b. Habitus lateral. c. Head, lateral. d–f. Male: d. Habitus dorsal. e. Habitus lateral. f. Head, lateral view. Abbreviations: mve: medial vitta (eye); sc: scale-like pile.

FIGURE 6. Orthonevra bellula (Williston, 1882), genitalia.a. Female, dorsal view. b. Female, ventral view. c. Male, epandrium, lateral view. d. Male, hypandrium, lateral view. Abbreviations: btp: basal tubular process; cerc: cercus; hypo: hypoproct; epi: epiproct; pg: postgonite; ph: phallus; sur: surstylus; surl: dorsal triangular lobe of surstylus; s8: sternum 8.