Macrostomus macerrimus ( Bezzi, 1909 )

Rafael, José Albertino & Marques, Dayse Willkenia Almeida, 2019, Five new species of Macrostomus Wiedemann and a checklist of Empididae (s. str.) (Diptera) from Bolivia, Zootaxa 4567 (2), pp. 251-275 : 257-258

Macrostomus macerrimus ( Bezzi, 1909)

( Figs 5 A–D)

Rhamphomyia macerrima Bezzi, 1909: 327 (syntypes ♂, ♀). Melander, 1928: 197; Collin, 1933: 211 (cit).

Macrostomus macerrimus: Smith, 1961: 54 ; 1967: 30 (cat.); Rafael & Cumming, 2004: 446.

Diagnosis. Slender, shiny; thorax yellow-chestnut; abdomen black; legs yellow; wing slightly yellow, elongate with anal lobe and base narrow.

Redescription. Lectotype male. Body length from original description: “ 3.25–3.5 mm ”; wing length 3.9 mm. Head lost, originally described as “ oculis approximates, kopf mehr gerundet; Fühler ganz schwarz, mit allmählich verdüntem, ganz kurz behaartem dritten Gliede ” [head narrowly dichoptic, head more rounded, antenna black, postpedicel short setulose]. Head (of paralectotype male): Frons shiny brown to black, as wide as anterior ocellus width, narrowing ventrally. Two pairs of ocellar setae, posterior pair weaker. Face as wide as frons, widening ventrally. Postcranium shiny brown to black, gray pruinose, darker on postocular margin. Inner vertical and outer vertical setae subequal in length and equal to stouter ocellar setae and to uniseriated postocular row of setae; occipital setae restricted to dorsal half. Antenna dark brown to black with postpedicel short setulose. Proboscis as long as head height. Thorax (of lectotype): shiny yellow, brown on scutum, scutellum and mediotergite, more distinctly gray pruinose on disc of scutum, on postalar callus and on notopleuron and mediotergite. Thoracic chaetotaxy: 3 antepronotals small; 1 postpronotal stout, 1 weak; 4 dorsocentrals; 1 presutural supra-alar; 1 postsutural supra-alar; 1 postalar; 4–5 minute proepisternals; 3 notopleurals stout ( M. limbipennis species-group described as two notopleurals); 2 pairs of scutellars, inner pair stouter, convergent; 5 laterotergitals. Legs yellow with apex of all tibiae and all tarsi entirely brown. Legs longer setae: fore tibia with posterior row of setae slightly longer than remaining setae, additionally with 1 anterodorsal and 1 posterodorsal slightly stouter; fore tarsomeres with anterodorsal and posterodorsal setae stouter distally; mid tibia with 1 anterodorsal on basal fifth and 1 posterodorsal, 1 anteroventral and 1 posteroventral distally, latter two shorter; mid tarsomeres with distal setae stouter; hind tibia with 1 posterodorsal on basal fifth, 2 posteroventral and 1 anterodorsal on distal two fifth; hind tarsomere 1 with 1 median slender dorsal seta. Wing ( Fig. 5A ) slightly yellow infuscated; pterostigma somewhat inconspicuous; veins M 1 and M 2 somewhat distinct; vein CuA+CuP evanescent; last section of vein M 4 longer than vein dm-m; cell dm truncate. Halter yellow to light brown. Abdomen shiny black with blue metallic reflection and tergite 1 yellow ventrally. Tergite 8 ( Fig. 5B ) wider at base, with deep distal cleft. Sternite 8 with distinct saddle- shaped projection posterodorsally. Epandrium subquadrate, anterodorsal and posterodorsal lobes approximately of same length with small protuberance between them, with longer setae on posterodorsal lobe. Anterior cercus ( Figs 5C, D ) elongate, subrectangular, sinuose dorsally and ventrally. Cercal bridge not observed in detail, but distinctly placed anteriorly and close to tergite 8. Median cercus membranous, pedunculate, with slender anterodorsal marginal setae. Posterior cercus ( Figs 5C, D ) sclerotized, elongate, inwardly curved with wide mesial projection and wide bifid distal projection. Hypandrium ( Fig. 5C ) with longer setae posteriorly. Ejaculatory apodeme tetralamelar, dorsal lamella higher. Phallus as long as hypandrium with apex somewhat blunt.

Female (paralectotype) as in male, except face slightly narrower than frons; outer vertical seta smaller than inner vertical and ocellar setae. Abdomen lost, described as “ terebra basi inflata lamellis terminalibus angustis ” [terminalia with segment 8 wider basally].

Geographical records. Bolivia (La Paz).

Type material examined. LECTOTYPE ♂ (here designated), Paralectotype ♂, on same pin: “ BOLIVIA [La Paz], Mapiri, Sarampioni , 22.ii.1903 ” ( SMTD) . PARALECTOTYPES: Mapiri, Sarampioni, 16.ii. 1903, 700 m (1♀, SMTD, wings and abdomen lost); Mapiri, Sarampioni, 25.ii.1903 (1♂, SMTD, wings, left mid leg, hind legs and abdomen lost) .

Lectotype condition. Head, fore legs and right mid leg lost, right wing mounted on microslide, abdomen in microvial with glycerin.

Variation. Macrostomus macerrimus has four dorsocentrals unlike most other species of the M. limbipennis species-group, which have three dorsocentral setae.

Remarks. Lectotype designated accordingly to fix and stabilize the current concept of the name

Figures

FIGURE 5. Macrostomus macerrimus (Bezzi, 1909), lectotype ♂. A. Wing; B. Tergite 8, dorsal view, setae omitted; C. Terminalia, lateral view; D. Details of cerci and cercal bridge. Scale bars, figures A = 1 mm; B–C = 0.2 mm. Abbreviations: ACe, anterior cercus; cbrd, cercal bridge; MCe, median cercus; PCe, posterior cercus.