Neomochtherus proshchalykini sp. nov.

Figs 1–13, 23

Diagnosis. (Figs 1–12). Body length 13.5–17.5 (holotype 14.0) mm. Mystax white. Orbital and ocellar setae white (Figs 1–4). Postocular setae and macrosetae white. Scutellum with 2 white apical macrosetae and few long white setae (Fig. 4). 2–3 postsutural dorsocentral macrosetae white and black, not reaching transverse suture, 2 notopleural, 2 supra-alar and 2 postalar macrosetae white, black sometimes (Figs 1, 3–4). Fore, mid and hind femora black. Fore, mid and hind tibiae black, brownish at base. For, mid and hind tarsi black (Figs 1, 3). Tergites black with reddish-brown stripe posteriorly without setae in dorsal view. Tergites I–IV, sometimes V, with 2–3 distinct goldish macrosetae at margin before the reddish-brown stripe in lateral view (Fig. 1). Hypopygium black with white setae (Figs 3–4).

Description. Male (Figs 1–12). Body length 13.5–17.5 (holotype 14.0) mm. Head black. Facial gibbosity small. Face, frons and vertex silvery brown tomentose. Mystacal macrosetae and setae white, longer than proboscis length. Upper margin of mystax does not reach middle of eye. Distance from upper margin of mystax to antennal sockets equal or longer than length of scape and pedicel combined. Palpus black with long white setae. Proboscis black with long white proboscial setae and short white labial setae. Orbital setae white. 4–9 ocellar setae white, shorter than length of scape. Postocular setae and macrosetae white. Occipital and lower occipital setae white. Antenna black, pedicel brownish at base. Postpedicel wide and flat, narrowed at apex, equal in length to scape and pedicel combined. Narrow style equal to postpedicel length, with seta-like sensory element. Scape and pedicel with white setae, postpedicel with few short setae (Figs 1–4).

Thorax black.Scutum with greyish and silvery brownish tomentum.Median and paramedian stripes,posthumeral, pre- and postsutural spots scarcely tomentose. Mesonotal setae: 2–3 postsutural dorsocentral macrosetae white and black, not reaching transverse suture. 2 notopleural, 2 supra-alar and 2 postalar macrosetae mostly white, but black sometimes. Scutum with short black setae. Pleuron black, silvery brownish tomentose and without setae, katepisternum with few long white setae dorsally. Katatergite with row of white setae and macrosetae. Postpronotal lobe without setae. Scutellum silvery brownish tomentose, with 2 white apical macrosetae and few long white setae; disk with long white setae. Lower margin of scutum with long, sparse, white setae posteriorly (Figs 1, 3–4).

Wings slightly darkened due to brownish microtrichia, veins brown (Fig. 4).

Legs. Coxae black, silvery tomentose, with long white setae and macrosetae. Trochanters black with silvery tomentum. Fore, mid and hind femora black with short white setae. Fore femur with row of long white setae ventrally. Mid and hind femora with few white macrosetae. Fore, mid and hind tibiae black, brownish at base, especially in fore and mid tibiae. Tibiae with short white setae and few white macrosetae. Fore, mid and hind tarsi black with white and black setae and macrosetae. Claws black, reddish yellow at base. Pulvilli well developed, reddish yellow, reaching 2/3 of claw length (Figs 1, 3).

Abdomen. Tergites and sternites black with greyish and silvery brownish tomentum. All tergites with reddish-brown stripe posteriorly without setae in dorsal view (Figs. 1, 3–4).All sternites with reddish-brown stripe posteriorly without setae in ventral view. All short setae on tergites and sternites mostly goldish, with some white. Tergites I–IV, sometimes V, with 2–3 distinct goldish macrosetae at margin before reddish brown stripe in lateral view. Sternites I–V often with 1–2 macrosetae at margin before the reddish-brown stripe on both sides in ventral view. Sternite VII with distinct narrow outgrowth with thick setae at posterior margin.

Hypopygium large, 1.7 mm in length, black with white setae (Figs 3–4). Posterior margin of epandrium uneven, with straight lobe-shaped and sharp projections. Gonostylus elongated and extends beyond apex of gonocoxite. Phallus elongated and curved downward in apical quarter. Ejaculatory apodeme of medium sized (Figs 7–12).

Body length range 13.5–17.5 (holotype 14.0) mm.

Female. Similar to male, but slightly longer in length. Femora black, tibiae dark brown with black stripes anteriorly and posteriorly. Tarsomere I brown, tarsomeres II–V brown with black apexes (Figs 5–6).

Material examined. Holotype, ♂: Russia, Altai Republic, Kosh-Agachsky Distr., 5 km SE Chagan-Uzun, Tydtuyaryk Riv., h= 1780 m, [50º4’22’’N 88º25’12’’E], 10.VII.2016, V. Sakhvon, ♂ (BSU). Paratypes: same place, 10–13.VII.2016, V. Sakhvon, ♂, 6♀ (BSU); same place, 10.VII.2016, V. Sakhvon, ♂, ♀ (FSC); same place, 13.VII.2016, V. Sakhvon, ♂, ♀ (MSU); 3,5 km SWW Chagan-Uzun, near Mars, h= 1755 m, [50º4’26’’N 88º21’17’’E], 23–25. VI.2022, V. Sakhvon, 4♂, 2♀ (BSU).

Distribution. Russia (Altai Republic).

Etymology. This species was named after my dear friend Russian hymenopterist Maxim Proshchalykin, who was the organizer of expeditions to Altai and helped me collecting robber flies.

Habitat. Neomochtherus proshchalykini sp. nov. was collected in the Altai Mountains, in a mountain semi-desert with sparse herbaceous vegetation and scattered shrubs of Caragana bungei Ledeb. (Fabaceae) (Fig. 13, 23). Robber flies are quite common in such habitats and prefer being in open areas of the ground without any vegetation. We observed that when disturbed, they flew several meters and sat down again on the ground.

Remarks. Only 2 species of Neomochtherus Osten Sacken, 1878 (N. yasya Lehr, 1996 and N. variabilis (Lehr, 1964) (Lehr 1964, 1996)) are found in territories bordering the Altai Republic. The male of the new species differs by having a white mystax (mystacal macrosetae and setae mixed white and black in N. yasya and mixed white, yellow and black in N. variabilis), by having black femora (black with reddish at apex in both N. yasya and N. variabilis), by having white setae and macrosetae on femora and lacking the row of macrosetae ventrally on mid femur (mid femur with 2 rows of black macrosetae in N. yasya and fore and mid femora with white, yellow and black setae and macrosetae in N. variabilis), by having 2 white apical scutellar macrosetae (2–6 in N. yasya and 4–6 in N. variabilis) and also by phallus curved downward in the apical quarter (phallus straight in apical quarter in both N. yasya and N. variabilis).