Adult males have bipectinate antennae and brownish-grey coloration. The main diagnostic feature in the clasping apparatus is an enlarged outgrown ampulla (digitus sensu Saldaitis et al. 2022), whereas the ampulla of other Psaphidini, if present, is smaller and does not rise above the surface of the valva. The vesica has anterior and posterior elasmas at the base of the vesica ejaculatorius, which are flat, sclerotized plates or raised, volumetric, sclerotized plates with serrated surfaces. Elasma occur in some other genera of Psaphidini: Valeria Stephens, 1829, Meganephria Hübner, 1820, Benedekia Ronkay, Ronkay, Gyulai & Hacker, 2010, and Allophyes Tams, 1942; however, the combination of robust ampulla and both anterior and posterior elasmas are unique within the tribe.

Himalaea (Macrohimalaea) silvana sp. nov., here designated.

The new subgenus differs from the nominotypical one in having shorter rami, and 1.3–1.5 times longer forewings with tapered apices (compare Fig. 1 with Figs 2–4). The male genitalia have an even-surfaced anellus, a dorsad elongated juxta, a sclerotized costa reaching the apex of the cucullus, a less-sclerotized ampulla lacking a harpe, an unpronounced carina, larger dorsal diverticulum bearing cornuti, and flat anterior elasma (compare Fig. 5 with Figs 6–8).

Figures 1–4. 

Adult males and enlarged antennae of Himalaea spp.; depositories of adults. 1. HNHM (photo © B. Tóth); 2. AFM; 3, 4. TU. Scale bars: 1 cm.

Figures 5, 6. 

Male genitalia of Himalaea spp.; depositories of slides. 5. HNHM (photo © B. Tóth); 6. AFM.

Figures 7, 8. 

Male genitalia; depository of slides: XU.

Adult male (Figs 2–4). Antenna bipectinate, rami gradually elongating towards mid third of antenna and then gradually shortening in distal third. Head, thorax, and abdomen dorsally brown-mottled, abdomen dark brown to blackish brown. Forewing 23.3 mm long; somewhat triangular, elongate and relatively narrow with obtuse tornal angle, slightly crenulate outer margin, prominence at M3, and tapered apex. Pattern consists of basal, medial, subterminal and terminal fields, with subterminal field being the lightest; dark basal streak within claviform spot bordered with dark wavy antemedial line; orbicular spot a little smaller than reniform spot, both with dark contour; dark, crenulate postmedial line; blurred, dark streak from posterior margin of reniform spot towards apex of wing; blurred, dark, zigzag subterminal line; more or less pronounced dark tornal streak; and dark terminal line split interrupted at veins. Cilia brown-mottled. Hindwing somewhat triangular with rounded apex and slightly crenulated outer margin; light-colored, getting darker at distal margin of discal cell. Cilia brown-mottled. Male genitalia (Figs 6–8). Uncus somewhat digitiform, basally bent at around 90°, apically narrowed to pointed apex. Tegumen a band narrowing towards connection with vinculum. Vinculum somewhat longer than tegumen, ventrally forming U-shaped saccus. Valva elongate, about the size of tegumen-vinculum complex, with well-pronounced sclerotized costa and sacculus, membrane between them, and membranous valvula, all sparsely covered with setae; distal third of costa less sclerotized, medially connected with relatively short (in comparison to Himalaea) editum bearing ampulla; sacculus narrowing towards barely protruded rounded distal apex; both valvae joint with tendon. Juxta an elongated plate narrowing distally. Anellus small with smooth surface. Phallus as long as valva, slightly bent medially, with elongate coecum and wide entrance of ductus ejaculatorius; vesica somewhat conical, downcurved, with dorsal spherical diverticulum bearing three or four cornuti; at base of vesica ejaculatorius, anterior elasma flat, posterior elasma may be raised or flat. Adult female unknown.

The name Macrohimalaea is a derivative from Himalaea, the type subgenus of the genus, and prefix macro- for big or large to indicate that the specimens of Macrohimalaea are larger than the ones of Himalaea.

Holotype : • 1 male, “TU-01084/ At the junction of Bahe Town (Gongbu Jiangda County) and Baiba Town (Bayi District) / Baiba Town / Bayi District, Linzhi City, / Xizang / N 29° 52’ 22.09” / E 92° 31’ 31.96” / 23.8.2004 h 4203.7m (coll. XU),” GS prepared by Chen Enyong (XU).

Paratype : • 1 male, same data but “TU-01083” (XU).

The new species differs from H. (M.) batanga in having thicker rami, less contrasting forewings, and slightly darker hindwings (compare Figs 3, 4 with Fig. 2). The male genitalia which are lacking a clavus have wider ampulla, an unprotruded costa, a downcurved phallus, cornuti at the top of the dorsal diverticulum, and flat posterior elasma (compare Figs 3, 4 with Fig. 2). The new species was collected within the Northeast Himalayan subalpine coniferous forest ecoregion, which contrasts with H. (M.) batanga, which was collected within the Southeast Tibet shrublands and meadows.

Male (Figs 3, 4). Antenna bipectinate, rami gradually elongating towards mid third of antenna and then gradually shortening in distal third. Flagellum covered with greyish scales. Head dorsally, patagium and tegula grey-mottled. Thorax dorsally dark grey-mottled. Abdomen dorsally greyish-brown mottled at tergites II to III and at distal tip, whereas tergites IV to VIII covered with blackish scales. Forewing 23.3 mm long; somewhat triangular, elongate and relatively narrow with obtuse tornal angle, slightly crenulate outer margin, prominence at M3, and tapered apex. Pattern consist of greyish-brown mottled basal, medial, subterminal and terminal fields, with subterminal field being the lightest; dark-brown, narrow, basal streak inside light-greyish-brown claviform spot bordered with dark-brown, wavy antemedial line; orbicular and reniform spots with light-brown and sparse dark-brown scales and dark-brown contour; dark-brown, crenulate postmedial line; blurred, dark-brown streak from posterior margin of reniform spot towards apex of wing; blurred, dark-brown, zigzag subterminal line with whitish posterior streaks; more or less pronounced dark-brown tornal streak; and blackish terminal line interrupted at veins. Cilia greyish-brown mottled. Hindwing somewhat triangular with rounded apex and slightly crenulated outer margin. Light brown, getting darker at distal margin of discal cell and towards outer margin. Cilia brown-mottled. Male genitalia (Figs 7, 8). Uncus somewhat digitiform, basally bent at around 90°, apically narrowed to pointed apex. Tegumen a band narrowing towards connection with vinculum. Vinculum somewhat longer than tegumen, ventrally forms U-shaped saccus. Valva elongate, about the size of tegumen–vinculum complex, with well-pronounced sclerotized costa and sacculus, membrane between them, and membranous valvula, all sparsely covered with setae; distal third of costa less sclerotized, medially connected with rather short editum bearing somewhat trapezoidal ampulla with wavy distal margin and two lateral rounded apices, posterior one two times longer than anterior one; sacculus narrowing towards barely protruded rounded distal apex; both valvae joint with tendon. Juxta an elongated, distally narrowing plate. Anellus small, with smooth surface. Phallus as long as valva, slightly downcurved medially, with elongate coecum and wide entrance of ductus ejaculatorius; vesica somewhat conical, downcurved, with dorsal spherical diverticulum distally bearing three or four aligned cornuti, two elasmas pronounced at base of vesica ejaculatorius: anterior one somewhat oval, with fuzzy margin, weakly sclerotized (Fig. 8), and posterior one somewhat oval or heart-shaped with well-pronounced proximal margin and fuzzy distal margin, sclerotized harder than anterior one. Female unknown.

The type series was collected from an altitude of 3,200 m on 23 August between 21:10 p.m. and 1:20 a.m. when the temperature was 15–16 °C and the relative humidity was around 60%. Adult moths collected there belonged to the families Noctuidae, Geometridae, Lasiocampidae, and Cossidae, with Noctuidae dominating in both numbers of species and individuals. The collection site was at the bottom of an alpine valley where the plant community was primarily dominated by Pinus densata and Quercus aquifolioides, while the main plant community at the valley floor consisted of small shrubs. The collecting site lies within the Northeast Himalayan subalpine coniferous forest ecoregion.

Figures 9–11. 

Collecting localities of Himalaea (Macrohimalaea subgen. nov.) silvana sp. nov. 9. Physical map (map data ©2025 Google); 10. Ecoregional map (image ©2025 TerraMetrics); 11. Habitat.

The name silvana is a feminine derivative from the Latin noun silva meaning forest, given to the species for its occurrence near the Northeast Himalayan subalpine coniferous forest.