Acalyptris minimella (Rebel, 1926)

Description. Male. Forewing length 1.8–2.4 mm, wingspan 4.1–5.4 mm. Head: frontal tuft ochreous white to yellowish orange, occasionally mixed with fuscous; collar paler; scape and pedicel yellowish white. Antenna with ca. 32–39 segments. Thorax and forewing yellowish ochreous, irrorate with few pale brown scales; cilia white, cilia line not distinct. Underside at base with small central pale yellow spot, formed by lamellar androconial scales, remaining part darker; along dorsal margin at base a hair-pencil mixing with hindwing hair-pencil. Hindwing frenulum and costal bristles present; with field of yellowish hair and lamellar scales in basal 1/2, forming an indistinct hair-pencil; underside greyish white. Abdomen yellowish grey, with grey inconspicuous anal tufts.
Female. Forewing length 2.1–2.6 mm, wingspan 4.7–5.8 mm. Antenna with 28–33 segments. Thorax and forewing somewhat darker than in male; special scales absent; costal bristles present. Abdomen with wide ovipositor, no anal tufts.
Male genitalia. Measurements: see Table 3. Vinculum anteriorly concave, ventral plate not large. Tegumen small, more or less triangular; uncus band-shaped, with indistinct central process, in lateral view split distally; gnathos with long narrow central element. Valva narrow, with large, more or less triangular, basal inner process; apex slightly pointed. Transtilla without transverse bar, sublateral process distinct. Aedeagus with bifurcate ventral carinae, tightly fused to V-shaped ventral process; a pair of curved dorsal carinae present; vesica with numerous small cornuti and one large cornutus.
Female genitalia. T8 narrow, with produced lateral corners, two small lateral groups of scales and setae. Anal papillae conspicuous, with 17–21 setae. Apophyses straight, slender. Total bursa length ca. 720–880 μm. Vestibulum with elaborate sclerotisations, more or less ring-shaped, inner margin partly serrate, with two processes. Ductus bursae covered with pectinations. Corpus bursae elongate, without pectinations; with narrow (2–3 cells wide) and long reticulate signa, margins crenate. Length shortest signum 270–320 μm, longest 340–385 μm. Ductus spermathecae with 3 convolutions and large vesicle.
Final instar larva. Head capsule ca. 325–350 μm wide. Mandibular cusps blunt. A9 with 3 pairs of setae. Integument covered with extremely short microtrichia (ca 1μm long) on all segments. Otherwise as group description.