Review of the genus Merulempista Roesler, 1967 (Lepidoptera, Pyralidae) from China, with description of two new species

Abstract The genus Merulempista Roesler, 1967 is reviewed for China. Of the four species treated in this paper, Merulempista rubriptera Li & Ren, sp. n. and Merulempista digitata Li & Ren, sp. n. are described as new; Merulempista cyclogramma (Hampson, 1896) is newly recorded for China, and its taxonomic position is briefly discussed. Photographs of the adults and genitalia are provided, along with a key to the known Chinese species.


Introduction
Merulempista Roesler, 1967 is a small genus of ten described species and subspecies, distributed in the Palaearctic Region except M. cyclogramma (Hampson, 1896) occurring in the Oriental Region and M. oppositalis (Walker, 1863) ranging from Oriental to Australian regions (Roesler 1984;Asselbergs 1997;Leraut 2001Leraut , 2002. Th e genus is characterized by the male gnathos distally hooked, the sclerotized costa often produced

Diagnosis.
Th is species is characterized by the rosy-colored forewing with a longitudinal greyish black stripe at base below costa. It can be distinguished from its congeners by the costa with a triangular distal process arising from 2/3 length of valva, the stout phallus with three thornlike cornuti located at middle in the male genitalia; and the antrum angularly protruding backward posterolaterally in the female genitalia.
Description. Adult (Fig. 3). Wingspan 23.5-24.5 mm. Head khaki in male, pale yellowish brown in female. Antenna with scape reddish brown dorsally, yellow ventrally; fl agellum yellowish brown ringed with brown; male sinus with shining deep greyish brown mixed with rosy scales, somewhat shelllike, pale yellow on ventral surface. Labial palpus pale yellowish white, densely covered with rosy scales ventrally, in female third segment tinged with black ventrodistally, far exceeding vertex; second segment shorter than diameter of eye, about 4 times length of third; third segment rather blunt apically. Patagium in male whitish yellowish tinged with pale yellowish brown, in female densely covered with greyish white-tipped rosy scales. Th orax and tegula in male rosy, in female greyish-brown tinged with rosy. Forewing rosy, with scattered greyish white and black scales in distal half, with a longitudinal greyish black stripe at base just below costa; posterior margin yellowish white at base; antemedian line yellowish white, straight, situated beyond basal 1/3, its posterior half tinged with black on inside, ocherous yellow on outside; postmedian and subterminal lines greyish white, slightly sinuate, nearly parallel; cilia rosy mixed with greyish brown, with a fi ne yellowish white basal line. Hindwing pale brown; cilia with basal 1/3 greyish brown, distal 2/3 greyish white. Legs rosy on outside, yellowish white on inside; tarsi brownish black, ringed with whitish yellow at apex of each segment, lined with short black spines on inside.
Female genitalia (Fig. 11). Papillae anales triangular, narrowed to bluntly rounded posterior margin. Eighth abdominal segment longer than wide, anterior margin roundly protruding, posterior margin straight. Apophyses anteriores about as long as apophyses posteriores, slightly dilated at base. Antrum weakly sclerotized, deeply concave at middle on posterior margin, angularly protruding backward posterolaterally. Ductus bursae membranous, with longitudinal rumples. Corpus bursae membranous, elongate ovate; large, more or less rectangular accessory sac arising from left side of corpus bursae posteriorly, densely covered with granules, ductus seminalis from its apex; signa comprised of two clusters of short spines, placed posteriorly.
Distribution. China (Inner Mongolia). Etymology. Th e specifi c epithet is derived from the Latin ruber (= red) and the suffi x -pteron (= wing), in reference to the color of forewing. Diagnosis. Th is species is similar to Merulempista cingillella, but diff ers in the clearly separated discocellular stigmata on the forewing; in the male genitalia the costa with distal process arising from 5/6 of the valva and in the female genitalia the antrum being triangular posterolaterally. In M. cingillella, the discocellular stigma on the forewing is kidney-shaped, the distal process of the costa arises from 3/4 of the valva, and the antrum is elongately leaf-shaped posterolaterally.

Merulempista digitata
Description. Adult (Fig. 4). Wingspan 22.0-27.0 mm. Head greyish brown to dark brown. Antenna with scape greyish brown to dark brown, twice longer than wide; fl agellum greyish yellow ringed with brown on dorsal surface, yellowish brown on ventral surface; male sinus with brush of brownish black scales. Labial palpus in male stronger than in female; fi rst segment greyish white, in male mixed with pale ochreous; second and third segments brown, mixed with pale ochreous except greyish white dorsally. Maxillary palpus columniform; in male golden yellow, about equal length to second segment of labial palpus; in female greyish white, slightly longer than third segment of labial palpus. Patagium pale reddish brown. Th orax and tegula brown tinged with greyish white except tegula pale reddish brown at base. Forewing three times longer than wide, apex rounded, termen bluntly oblique; ground coloration greyish brown to brownish black, mixed with reddish brown and greyish white; antemedian line white, extending from 1/4 of costal margin to 1/3 of posterior margin, edged with erect black scales along outside; discocellular stigmata brownish black, clearly separated, forming two distinct spots; postmedian line white, dentate, parallel with termen; termen pale brown to brownish black, discontinuous, sometimes forming small dark spots; cilia grey mottled brown. Hindwing pale grey; cilia yellowish white.
Male genitalia (Fig. 8). Uncus wide at base, narrowed toward bluntly rounded apex, length as long as basal width. Gnathos dilated basally, slender and pointed distally, hooked apically, about 2/5 length of uncus. Costa wider than sacculus; distal process fi ngerlike, arising from about 4/5 length of valva, forming an acute angle with valva at outside, bearing a needlelike apical prong slightly exceeding end of valva. Valva about four times longer than wide, basal half slightly narrower, widened and arciform ventrally from middle to 5/6; distal 1/6 triangularly shaped, densely covered with long setae, narrowly rounded at apex; clasper fi nger-shaped, blunt apically; sacculus about half length of valva, basal half slightly wider than distal half. Vinculum broad, U-shaped; anterior margin slightly concave inward at middle. Juxta V-shaped; lateral lobe narrowed distally, curved inward. Phallus about same length as valva, thick at base; with three needle-like cornuti, longest one about 3/5 length of phallus, located medially, other two placed distally. Eighth sternite and culcita shown in fi gure 8a.

Merulempista cingillella
Hostplants Diagnosis. Th is species is conspicuously diff erent from its congeners by the costa of valva weakly sclerotized and lacking the distal process, the juxta with gradually broadened, posteriorly rounded and spinulate lateral lobe, and the vinculum with a small papillate anteromedian process in the male genitalia; and by the antrum deeply and widely concave at middle, elongate featherlike posterolaterally in the female genitalia.
Remarks. Of the four species described in this paper, M. cyclogramma is the only one that is distributed in the southern part of China, while the other three occur in the northern and northwestern parts of China (Fig. 2). Taking the genital structures into consideration, the taxonomic position of this species needs further study with additional material.
Th is species is recorded as new for China.