Mesembrius ingratus (Loew, 1858)

Jordaens, Kurt, Goergen, Georg, Skevington, Jeffrey H., Kelso, Scott & Meyer, Marc De, 2021, Revision of the Afrotropical species of the hover fly genus Mesembrius Rondani (Diptera, Syrphidae) using morphological and molecular data, ZooKeys 1046, pp. 1-141 : 1

publication ID	https://dx.doi.org/10.3897/zookeys.1046.57052
publication LSID	lsid:zoobank.org:pub:66E61C4E-FAFE-45DE-9145-DB38199BDEC3
persistent identifier	https://treatment.plazi.org/id/579D9241-28DE-5AFF-974E-995F3D727CA1
treatment provided by	ZooKeys by Pensoft
scientific name	Mesembrius ingratus (Loew, 1858)
status

Treatment

Mesembrius ingratus (Loew, 1858) Figs 11 View Figures 11, 12 , 54 View Figures 52–57 , 91 View Figures 89–94 , 133 View Figures 131–134 , 158, 190 View Figures 189–192 , 213 View Figures 205–216

Helophilus ingratus Loew, 1858: 380.

Helophilus ingratus - Loew (1860): 386 - Hervé-Bazin (1914a): 297.

Helophilus (Mesembrius) ingratus - Bezzi (1915): 97.

Tubifera ingrata - Kertész (1910): 254.

Mesembrius ingratus - Curran (1927): 60 - Szilády (1942): 92 - Smith and Vockeroth (1980): 504.

Differential diagnosis.

Mesembrius ingratus males are holoptic, have a loose black apical pile brush on the profemur, a densely yellow pilose scutum with vague longitudinal vittae, a tuft of black pile on the posterior side of the probasitarsus, a slender metatibia and a posterior deep depression in the proximal half of the metatibia which ventrally extends into a deep groove. It can be distinguished from any other species by the apical pile brush of the profemur which is loose and yellowish with some black pile interspersed (black dorsally, yellow ventrally in M. arcuatus sp. nov.; black in M. tarsatus ) and by the deep groove on the metatibia (strongly compressed in M. arcuatus sp. nov.; with a rounded swelling in M. tarsatus ). The female is unknown.

Examined material.

Helophilus ingratus Loew: Holotype, male, " Helophilus // Helophilus ingratus " “209” “209” " HOLOTYPUS // Helophilus ingratus // Loew, 1858" "design. Kassebeer 1993" "NHRS-BYWS // 000002619" [NRMS].

Other material

Malawi • 1♂; Mount Mulanje ; 20 Oct 1912; S.A. Neave leg.; NHMUK. Senegal • 2♂♂; Dakar ; 14 Jan 1945; collector unknown; RMNH. South Africa • 1♂; KwaZulu-Natal , Manguzi Forest Reserve ; 13-16 Dec 2010; J.G.H. Londt leg.; NMSA • 1♂; KwaZulu-Natal , St. Lucia Park Reserve ; 2 Feb 1988; J.G.H. Londt leg.; NMSA • 1♂; KwaZulu-Natal, Ngoya Forest Reserve ; 26 Apr 1988; J.G.H. Londt leg.; NMSA .

Re-description male

(Fig. 11 View Figures 11, 12 ). Body length: 10.9-11.1 mm. Wing length: 8.0-8.4 mm.

Head (Fig. 54 View Figures 52–57 ). Eyes bare; holoptic, length of eye contiguity approx. 1/3 the length of ocellar triangle. Face white with dark medial vitta; white pilose; white pollinose. Vertical triangle with black pile in ventral half and at ocellar triangle; yellow pilose in dorsal half; yellow pollinose. Distance between lateral ocellus and eye margin 1/2 width of ocellus. Frontal triangle and gena white; white pilose; white pollinose. Frontal prominence shiny black; black pilose. Occiput black, but strongly white-grey pollinose; yellow-brown pilose, with a row of almost equally long black pile at dorsal eye margin. Antenna reddish-brown.

Thorax. Scutum dark brown with dorsally a pair of vague yellow vittae; yellow-brown pilose. Scutellum uniformly light yellow-brown; yellow pilose.

Legs. All legs dark brown, except for pro- and mesotarsi which are yellow-brown. All femora and tibiae with long, loose yellow pile. Proleg (Fig. 158): Femur with a loose, yellow apical pile brush interspersed with some long black pile; very short thick pile and longer thin black pile at proximal 1/4 ventrally. Tibia with long, black pile, except dorsally. Basitarsus black pilose dorsally, with tuft of black pile on posterior side, short orange pilose ventrally. Other tarsi black pilose dorsally, short orange pilose ventrally. Mesoleg: Femur long yellow pilose posteriorly and posterodorsally, except at distal end where pile is black; short black pilose anteriorly and anterodorsally; ventrally with longer black pile. Tibia long black and short yellow pilose. Tarsi short black pilose dorsally; short yellow pilose ventrally with a few thick black spines. Metaleg (Fig. 190 View Figures 189–192 ): Femur very slender; covered with long, thin yellow pile; shorter black pile on ventral 1/4 and at distal end. Tibia with a deep posterior depression in the proximal half which is extended as a groove on the ventral side, demarcated with short, dense black pile; proximal half dorsoventrally flattened; predominantly black pilose. Tarsi black pilose dorsally; orange pilose ventrally.

Wing (Fig. 133 View Figures 131–134 ). Entire wing uniformly dense microtrichose.

Abdomen (Fig. 91 View Figures 89–94 ). Tergite II with pair of very large, yellow triangular maculae; yellow pilose; black marking hourglass-shaped; posterior black marking equal in size or somewhat narrower than anterior black marking, but more vague because of medial white pollinosity; posterior black marking with black pile that posterolaterally extends into the yellow maculae. Tergite III with yellow fascia of variable size, occupying approx. the entire tergite; yellow pilose; with posterior, triangular black marking; black pilose; white pollinose. Tergite IV black; white pilose and white pollinose on anterior fascia, black and yellow pilose on remainder of tergite.

Genitalia (Fig. 213 View Figures 205–216 ). Epandrium: Dorsal lobe of surstylus somewhat elongated, broadly rounded, with short, black spines on almost entire surface; dorsally long yellow pilose. Ventral lobe of surstylus straight; bare.

Female.

Unknown.

Distribution.

Malawi, Senegal and South Africa.

Comments.

Curran (1927) cites several specimens from three localities in the Democratic Republic of the Congo. In a later publication, Curran (1939) suggests that these specimens belong to M. tarsatus. Bezzi (1915) also mentions the species from Uganda and Durban in South Africa, but Curran (1939) also considers these specimens as M. tarsatus . We have not encountered females that could be associated with the male of M. ingratus . No DNA barcodes are available for M. ingratus .