Review of Pseudacrobasis Roesler, 1975 from China (Lepidoptera, Pyralidae, Phycitinae)

Abstract The genus Pseudacrobasis is reviewed for China. Pseudacrobasis dilatata sp. n. is described as new and compared with Psorosa tergestella (Ragonot, 1901). Images of adults and illustrations of genital structures are provided.

It has been more than 40 years since the genus establishment, and since then the type species Pseudacrobasis tergestella (Ragonot, 1901) is known only. Here, a second species P. dilatata sp. n. is described, based on specimens collected from different localities in China, and it is compared with P. tergestella (Ragonot, 1901).

Material and methods
Genitalia dissections were carried out following the methods introduced by Li (2002). Photographs of adults and venation were taken with a Leica M205A, and photographs of genitalia and details of the head were taken with a Leica DM750, using Leica Application Suite 4.6 software to capture images. The type specimens are deposited in the Insect Collection of Nankai University, Tianjin, China.
Diagnostic characters. Pseudacrobasis is characterized by the combination of the following characters: the male antennal scape with a distal scale projection on the inner side, the several basal flagellomeres slightly incurved, forming a shallow sinus containing a smaller scale tuft, the first and several other flagellomeres beyond the sinus bearing a small spine dorsally (Figs 1c, 2c), the ventral surface of the flagellum bearing dense, elongate cilia approximately as long as width of the flagellum, the female antenna simple and weakly pubescent; the labial palpus upturned just beyond the vertex (Figs 1a,1b,2a,2b); the forewing having a fuscous patch on the inner side of the antemedial line and a tuft of scales near the fuscous spot, R 3 + 4 and R 5 stalked in basal 2/3, M 2 and M 3 very shortly stalked; the hindwing with Rs and Sc stalked for basal 2/5 of Rs, M 2 and M 3 long-stalked ( Fig. 1d) or fused (Fig. 2d), M 2+3 shortly stalked with CuA 1 ; in the male genitalia, the apical process of the gnathos tapered, the separated transtilla strongly sclerotized, the valva with a small fingerlike clasper at base, the U-shaped juxta with a pair of finger-like lateral lobes, and the phallus with many slightly sclerotized crimples and microtrichia (Figs 3,4); in the female genitalia, both apophyses anteriores and posteriores of medium length, the former slightly shorter than the latter, the antrum weak-sclerotized or not sclerotized, the membranous ductus bursae with many spinules near the junction with the corpus bursae, the ovate membranous corpus bursae shorter than the ductus bursae, the signum developed as a small, rounded, granulate plate, and the ductus seminalis arising from the corpus bursae posteriorly (Figs 5, 6).
This genus is similar to Caradjaria Roesler, 1975 in appearance, but can be distinguished from the latter by the following characters: the male antennal scape with an angular scale process at its inner terminal, which disappears once the scales are removed; the forewing with M 2 and M 3 very short-stalked; the apical process of the gnathos tapered, the transtilla separated, and the phallus with sclerotized wrinking and a few minute and weak scobinations in the male genitalia; and the membranous corpus bursae in the female genitalia. In the genus Caradjaria, the male antennal scape is enlarged at its inner terminal to form a thorn-like process; M 2 and M 3 of the forewing are stalked approximately half of their length; the apical process of the gnathos is enlarged in distal part, the transtilla is connected, and the phallus has small dense spines in the male genitalia; the corpus bursae of the female genitalia is weakly sclerotized in its posterior half.
Notes. Pseudacrobasis tergestella (Ragonot, 1901) is widely distributed in China. Its identification in this study is based on the examination of 88 male and 67 female specimens. Scalercio (2015) pointed out "the currently known […], the distribution of P. tergestella is quite unique with occurrences in the far east and in the far west of the Palearctic region, no records are currently available for Central Asia and East Europe, where suitable habitats are present". We believe P. tergestella is likely to distribute the Central Asian and East Europe region with the depth of the investigation.

Pseudacrobasis dilatata sp. n.
http://zoobank.org/AD43828F-F38B-4D24-929D- 4F9EC463A172  Figs 1, 3, 5 Diagnosis. This new species can be distinguished from its allied species P. tergestella by the following characters: M 2 and M 3 of the hindwing stalked for approximately 3/5 of their lengths; in the male genitalia by the subtriangular uncus gradually narrowed to truncate apex, the transtilla with its distal part developed into two small horns of nearly equal sizes; in the female genitalia by the posterior margin of the eighth tergite only slightly concave and lacking decoration. In P. tergestella (Figs 2, 4, 6), M 2 and M 3 of the hindwing are completely fused (Fig. 2d); in the male genitalia, the uncus is mushroom-like in distal 2/5, the distal part of the transtilla is developed as one large and one small horns (Fig. 4); in the female genitalia, the posterior margin of the eighth tergite is deeply concave and U-shaped, and has a sclerotized semicircular mark in the middle of the anterior 1/3 (Fig. 6).