(Plate 10, figure 3; male genit. plate 19, figure 5; female genit. plate 25, figure 6)

Material examined. Holotype: male, Vietnam N, 5 km E Bao Loc, Suoi Loc stream, 24.x.1988, leg. S. Mahunka, J. Oláh & T. Vásárhelvi, coll. HNHM.

Paratypes: 2 males, 1 female: same data as holotype; 2 males genit. preps 5922 and 5924, and 1 female genit. prep. 5923 M. Fibiger. Colls HNHM and MF.

Diagnosis. Imago (external). Wingspan: 13–15 mm.

Forewing: purplish black.

Crosslines: black, indistinct, medial shade well marked.

Reniform stigma: distinct, round, yellowish, outlined black.

Hindwing: greyish brown, without discal spot.

Underside: unicolorous grey.

Abdomen: grey with black crest dorsally on first segment.

Male genitalia. Tegumen and fultura superior: dorsal part of tegumen weak, narrow; ventral part fused with fultura superior with a prominent, loglike process on each side, flattened at apices (apo.), right one shorter and apically broader.

Vinculum: short, loglike.

Saccus: short, V shaped.

Tergite: inconspicuous.

Valvae: slightly asymmetrical.

Sacculus: strongly asymmetrical, dorsally rounded, right one larger.

Ampulla: slightly asymmetrical, narrow medially.

Anellus: fused with juxta, forming full circle around phallus.

Phallus: broadest by ductus ejaculatorius, slightly curved clockwise, slightly tapered towards tip.

Vesica: basally with one small, triangular cornutus; subapically with row of 5 equally formed cornuti (apo.).

Female genitalia. Ovipositor: quadrangular, corners rounded.

Posterior apophyses: slightly longer than ovipositor.

7 th abdominal segment: heavily sclerotised, posteriorly U shaped by postvaginal plate from 8 th segment.

Ostium: slightly displaced to left, positioned anteriorly on 7 th segment.

Ductus bursae: long, cylindrical, slightly coiled, basal half membranous, apical half heavily sclerotised (apo.).

Corpus bursae: globular, with cross-shaped signum.

Differential diagnosis. B. basalia is in size above average for species of Bellulia. Unique in that processes from fultura superior rather short and flattened at apices; vesica with one basal and 5 subapical cornuti in a row; female genitalia with ductus bursae membranous in anterior half, heavily sclerotised in apical half.

Distribution. Known only from type-locality in North Vietnam.