Toxomerus dispar (Fabricius)

Mengual, Ximo, 2011, Black-tie dress code: two new species of the genus Toxomerus (Diptera, Syrphidae), ZooKeys 140, pp. 1-26 : 8-10

Toxomerus dispar (Fabricius) Figures 1-8

Syrphus dispar Fabricius 1794: 309. Type locality: "Americae meridionalis" restricted to Virgin Islands, St. Croix ( Thompson 1981: 86) [ST ♂ ♀, ZMUC, destroyed, see Thompson 1981: 86].

Syrphus basilaris Wiedemann 1830: 143. Type locality: Brazil [HT ♂, SMF].

Syrphus vicinus Macquart 1846: 264. Type locality: Brazil [HT ♀, OUMNH].

Mesogramma soror Schiner 1868: 350. Type locality: “America” [HT ♂, NMW]; Thompson et al., 1976: 48 (cat.).

Syrphus tridentatus Rondani 1868: 24. Type locality: Argentina, Patagonia [HT ♂, unknown].

Syrphus melanogaster Thomson 1869: 495. Type locality: Brazil, Rio de Janeiro [HT ♀, NHRS].

Mesograpta variabilis Wulp 1883: 6. Type locality: Guadeloupe, Delaunay [HT ♂, IRSNB].

Melanostoma annulifera Bigot 1884b: 84. Type locality: Mexico [HT ♀, OUMNH].

Mesograpta trilobata Bigot 1884b: 109. Type locality: Mexico [HT ♂, OUMNH].

Orthonevra annulifera Bigot 1884a: 556. Type locality: Brazil [HT ♀, OUMNH].

Paragus ruficaudatus Bigot 1884a: 541. Type locality: Brazil [HT ♂, BMNH].

Mesogramma -? (bidentata) Williston 1891: 25. Type locality: Mexico, Acaguizotla, Chilpancingo, Tepetlapa, Medellin near Vera Cruz, Teapa in Tabasco, Orizaba [ST ♂ ♀, unknown].

Mesogramma bidentatum Giglio-Tos 1893: 49. Type locality: Mexico, Acaguizotla, Chilpancingo, Tetetlapa, Medellin presso Vera Cruz, Orizaba, Tampico [ST 6♂ 3♀, MRSN].

Mesogramma imperialis Curran 1926: 103. Type locality: Jamaica, Blue Castle [HT ♀, BMNH].

Mesogramma lutzi Curran 1930: 7. Type locality: Panama, Canal Zone, Grijoles [HT ♀, AMNH].

Mesogramma basilaris var. flavocuneus Hull 1940: 433. Type locality: Honduras, Salada River, near Ceiba [HT ♀, CNC].

Mesogramma triangulata Hull 1942a: 104. Type locality: Paraguay, Villarica [HT ♀, AMNH].

Mesogramma basilaris var. bifida Hull 1943: 26. Type locality: Ecuador, Baños [HT ♂, CNC].

Mesogramma basilaris var. neotropica Hull 1943: 36.

Mesogramma lutzi var. fasciata Hull 1948: 8. Type locality: Venezuela. San Esteban [HT ♀, USNM].

Differential diagnosis.

Male has yellow face, females a medial broad black vitta continuing along frons and ending at vertex. Scutum black, bronze pollinose wit a medial whitish pollinose vitta and two submedial brown vittae; scutum black laterally except postpronotum yellow, at least on posterior half. Scutellum black, sometimes with apical margin yellow, pale pilose. Wing partly bare basally. Toxomerus dispar has the abdominal pattern very variable, from almost entirely yellow to entirely black (see Figs 1-5), and this is the main reason to have such a high number of synonyms.

Species very similar to Toxomerus sp. 3, but Toxomerus dispar has pro- and mesotibiae yellow, postanal process of male genitalia long, more than half as long as surstylus and female has metaepisternum partly or entirely yellow. The present key only works for dark forms of this species.

Length

(5): body, 6.4-7.1 (6.7) mm; wing, 5.1-5.4 (5.3) mm.

Distribution.

Widespread in the New World, from USA to Argentina.

Material examined.

More than 100 specimens from Mexico, Honduras, El Salvador, Guatemala, Costa Rica, Panama, Ecuador, Venezuela and Brazil.