Genus: Nilionympha Ren & Engel, 2007

Type species. Nilionympha pulchella Ren & Engel, 2007

Other included species. Nilionympha shantouensis sp. nov. ( N. imperfecta is transferred to Enodinympha imperfecta comb. nov.)

Emended diagnosis. Antenna filiform and extremely long. Forewing elongated, trichosors present in distal half of forewing; costal crossveins simple with occasional forks; Sc and R1 fused anterior to the wing apex; Rs with 12 branches, Rs1 diverged at one-third of wing length; MA separating from Rs at about one-fourth of wing length. Hind wing long and narrow, slightly similar with forewing; trichosors present; costal crossveins simple with occasional forks; Sc and R1 fused anterior to the wing apex; Rs with 10 to 11 branches, Rs1 diverged at one-third of wing length; MA separating from Rs at about one-fourth of wing length; MP forked apically; CuA branched from wing midlength; CuP pectinately branched; A1 distinct and near CuP.

Remarks. The genus Nilionympha was erected by Ren and Engel (2007: fig. 7–11), for which only the hind wing characters were provided in the original description. Unequivocally, Nilionympha belongs to the Gumillinae for the long antennae and relatively complicated venation, but its full comparison with the other gumilline genera was not possible due to the absence of the characters of forewing (Ren & Engel, 2007). After reexamining the type specimens of Nilionympha pulchella (Fig. 1A) and Nilionympha imperfecta (Fig. 1B), their fragmentary forewings were reconstructed in Fig. 1C ( N. pulchella) and Fig. 1D ( N. imperfecta). Although the forewing of the type species of N. pulchella is incomplete, some key characters can be detected to allow the possible comparison with other gumilline genera.

Nilionympha is most characterized by the numerous Rs branches in the forewing (12 branches), and this is clearly different from other gumilline genera (no more than seven branches). However, another genus Enodinympha established in the same paper with Nilionympha (Ren & Engel, 2007) also has similarly many Rs branches in forewing, but these two genera can be distinguished by the divergence of MA from Rs (Fig. 1C–E). Within Gumillinae, the divergence of MA from Rs is commonly distant to the wing base that forms multiple r1-mp crossveins as in Enodinympha translucida (Fig. 1E), while the separation of MA distinctly close to the wing base in N. pulchella (Fig. 1 C). Because the hindwing of Enodinympha translucida canot be fully reconstructed to provide the useful information due to the fragmentary condition of specimens, the both genera are still requested the further comparisons in future. It is notable that the species N. imperfecta (Fig. 1D) shows the similar configuration of MA with E. translucida (Fig. 1E) instead of N. pulchella . Additionally the configurations of CuA and CuP in the forewing of N. imperfecta also resemble those of Enodinympha (Fig. 1D, E), thus we deem it necessary to transfer N. imperfecta to Enodinympha as Enodinympha imperfecta comb. nov. (Fig. 1D). Furthermore, Sc and R1 amalgamate proximad of the pterostigma in N. pulchella, however, the fusion of Sc and R1 is much distal in the middle of pterostigma among most gumillines including the new species ( Nilionympha shantouensis sp. nov.) described below. Thus, we consider it a specific diagnosis and an autapomorphy of N. pulchella instead of the generic feature.