Macrostomus argyrotarsis (Bezzi)

(Fig. 2)

Rhamphomyia argyrotarsis Bezzi, 1909: 324 . Type locality: Bolivia, La Paz, Mapiri, San Carlos .

R. argyrotarsis: Melander, 1928: 186; Collin, 1933: 211 (cit.).

Macrostomus argyrotarsis: Smith, 1961: 53; 1967: 30 (cat.); Rafael & Cumming, 2004: 446; Yang et al., 2007: 145 (cat.); Rafael & Marques, 2019: 253 (figs 2A–C).

Diagnosis. Female. Body slender, shiny, thorax and legs mainly yellow; postcranium with only a pair of occipital setae behind inner vertical seta; legs without pennate setae; hind tarsomere 1 whitish to silvery, elongate; wing widely brown infuscate mainly in costal and apical margins, base narrowed and anal lobe very narrow; tergites 1 and 2 reddish-brown, shiny.

Male. Unknown.

Geographical records. Bolivia (La Paz); Peru (Madre de Dios).

Material examined. PERU: Madre de Dios, Mazuko, 13º02′51.1″S – 70º20′45.9″W, 382 m, 18.viii.2012, sweep, J.A. Rafael, R.R. Cavichioli, D.M. Takiya (1♀ MUSM) .

Remarks. This species was described from Bolivia and the holotype specimen was redescribed by Rafael & Marques (2019). In the same paper it was recorded from Peru. The Peruvian specimen (Fig. 2) differs from the Bolivian female holotype as follows: mesonotum mainly brown (versus mainly yellow in the holotype); hind tarsomeres 1–4 whitish to silvery (versus only tarsomere 1 whitish to silvery); wing with distal section of vein M 4 longer than vein dm-m height (versus same height of vein dm-m). Currently this species is known only from female specimens and despite these differences we tentatively prefer to consider the specimens from Bolivia and Peru conspecific until males from both locations are studied. This is essential in order to be confident that the Peruvian specimens are conspecific with Bolivian specimens.