Megachile (Chrysosarus) leucografa Friese, 1908

Roig-Alsina, A. & Torretta, J. P., 2021, The leucografa species group of Megachile (Chrysosarus) (Hymenoptera: Megachilidae), Journal of Natural History 55 (7 - 8), pp. 457-470 : 463-464

Megachile (Chrysosarus) leucografa Friese

( Figures 1 (a–b,e), 2(a–b), 5(a))

Megachile leucografa Friese, 1908: 63 , 67 (Lectotype female, Argentina, Mendoza, 18 December 1906, Jensen, ZMHU, designated by Durante et al. 2020).

Megachile trochantina Vachal, 1909: 14 (Lectotype male, Argentina, Mendoza, 20 January 1906, Rolle H., Berlim W., Museum National d’Histoire Naturelle, Paris, designated by Durante (1994). Synonymised by Durante et al. 2020.

Megachile perspicua Mitchell, 1930: 289–290 , pl. XIV (Holotype female, Argentina, Córdoba, Davis col., Museum of Comparative Zoology, Cambridge , USA, no. 16203) . Synonymised by Durante et al. 2020.

Megachile (Dactylomegachile) leucografa: Durante et al. 2020: 27–28 . (Synonymy, redescription.)

Diagnosis. Females of M. leucografa are distinguished by the short vestiture. Particularly distinctive are the scuto-scutellar band of short plumose hairs (0.3–0.6× MOD), the patch of hairs on the dorsolateral angle of the pronotum (hairs 0.5–0.8× MOD), and the patch of hairs behind the tegula (on the posterodorsal portion of the preaxilla) (hairs 0.6–1.1× MOD). The hairs on the disc of the scutum are up to 0.8–1.0× MOD, and those on the discs of T3–T4 are also short (0.4–0.6× MOD). Females of M. leucografa always have entire pale apical bands on T1–T5, pale hairs on T6, and whitish scopal hairs. The pale apical bands on T3–T5 have a yellowish tint, while in the other two species the bands are white. Males of M. leucografa are most similar to those of M. rancaguensis because of the dense pilosity of the hypostomal area, the extensive pale pubescence of the meso and metasoma, and the presence of an oblique row of hairs on the under surface of the forefemur ( Figure 1 (b) ‘r’). They differ from males of M. rancaguensis by the broadened last flagellomere of the antenna, the shorter pilosity of the scutum (hairs of disc up to 1.8× MOD), the weak angle near the middle of the lower margin of the mandible, the strong group of ferruginous setae on the forecoxa (7–12 setae up to 1× MOD), the yellowish colour of the tuft on the inner side of the mandible, and the yellowish colour of the hairs on the lower part of the gena. This species has been redescribed in detail by Durante et al. (2020), who also present a complete synonymy. The genital capsule and the sterna S5, S6 and S8 were illustrated by Durante (1994). This information is not repeated here.

Distribution. Argentina, provinces of Buenos Aires, Catamarca, Córdoba, La Pampa, La Rioja, Mendoza, Neuquén, Salta, San Juan, San Luis, Santiago del Estero and Tucumán ( Figure 5 (a)).

Material studied. All specimens cited by Durante et al. (2020, p. 28) were examined; their data are not repeated here, but they are included in the distribution map.

Figures

Figure 1. (a) Megachile leucografa, female, clypeus and mandibles; (b) M. leucografa, male, ventral view showing pilose hypostomal area, tuft of hairs on inner surface of mandible (‘t’), and oblique row of hairs on under surface of femur (‘r’); (c) M. obscurior, male, ventral view showing glabrous, rugose hypostomal area; (d) M. rancaguensis, male, ventral view showing pilose hypostomal area; (e) M. leucografa, female, hind tarsus; lines indicate measurements of length and width of basitarsus; (f) M. obscurior, male, dorsal view of apical metasomal terga. Scale bars: a, e = 0.5 mm; b–d, f = 1 mm.

Figure 5. Distribution of the species of the Megachile leugografa group. (a) Megachile leucografa (triangles); (b) M. obscurior (dots); and M. rancaguensis (stars).