Choristoneura expansiva Wang & Yang, sp. nov. (Figs. 1-3)

Type material. Holotype: ♂, China: Mt. Wuyi, Sangang, Fujian Province, 740 m, 19.v.2004, Yu Haili. Paratypes: 1 ♂, same data as holotype; 2 ♀♀, Mt. Wuyi, Pikeng, Fujian Province, 600 m, 27.v.2004, Yu Haili.

Diagnosis. The new species resembles C. luticostana superficially, but differs from it by the following: the distal half of the uncus is greatly expanded, the socius is vestigial, and the sacculus is free terminally. The male genitalia of C. expansiva are most similar to those of C. adumbratana, but the latter have the socius large, the uncus weakly broadening terminally, and the forewing with a distinct pattern.

Description. Adult (Fig. 1): Head: Labial palpus slender, length about 1.5 times diameter of compound eye, inner side yellowish white, outside gray brown. Frons gray, vertex with rough yellowish white scales. Antenna yellowish white. Thorax: Dorsum fulvous; tegula gray basally, yellowish white distally. Forewing length 17.0- 18.5 in male, 25.0- 26.5 mm in female. Forewing broad, costal margin distinctly convex, expanded apically; apex short, subsquare; termen straight at oblique angle, tornus broad; ground color grayish fulvous, without patterns, with some scattered short strigulae; costal fold short and narrow; fringe same color as ground color. Hindwing gray dark, fringe whitish gray. Legs yellowish white, foreleg tarsi with gray brown scales. Abdomen: Grayish brown dorsally, gray ventrally. Male genitalia (Fig. 2) with tegumen broad; uncus nearly as long as tegumen, narrow in basal half, greatly expanded in distal half, rounded apically, with dense brush of hairs ventrally; socius very small, vestigial; gnathos well developed, arms slender, terminal plate pointed apically. Transtilla band-shaped, expanded basally; valva oblong, simple; sacculus narrow, free terminally. Juxta broad, subtrapezoidal; aedeagus nearly as long as tegumen, curved, narrowed distally, with a large upward carina at tip; coecum penis short; caulis developed; no cornuti (possibly deciduous). Female genitalia (Fig. 3) with papilla analis broad and short; eighth tergite short; apophysis posterioris almost as long as apophysis anterioris; lamella postvaginalis broad, lamella antevaginalis narrow and short; antrum slender, with internal sclerite; ductus bursae very long, with long, narrow cestum nearly as long as ductus bursae; signum long, horn-shaped, with small external capitulum.

Etymology. The specific name is derived from the Latin word expansivus = expanded, referring to the distally expanded uncus.