Nemophora optima (Butler, 1878)

Liao, Cheng-Qing, Hirowatari, Toshiya, Yagi, Sadahisa, Wang, Min, Wang, Xing & Huang, Guo-Hua, 2023, The fauna of the family Adelidae (Insecta, Lepidoptera, Adeloidea) from China, Zootaxa 5348 (1), pp. 1-152 : 47-48

3.11 Nemophora optima species group

Diagnosis. This species group can be characterized by the following features: the compound eyes are very small, far away from each other, eye size index less than 0.5; the basal 2/3 of forewing ground color is yellow, with numerous black-margined silver-leaden fasciae; the apical 1/3 of forewing ground color is black, with some yellow radial striae; the basal 2/3 and apical 1/3 of the forewing are separated by two black-margined silver-leaden fasciae that are connected to each other or independent; and the vinculum is very long and slender, about 3.3 × as long as valva.

Remarks. The optima group consists of three species, namely N. optima ( Butler, 1878) , N. augantha ( Meyrick, 1907) , and one new species, N. conjugata sp. nov. from Guangxi, China herein. Among them, N. augantha (Plate XI-3) was only distributed in Assam, India and has not been reported since its original description. In addition, N. optima was originally described in Japan, and is first reported in China here.

Key to species of the optima group based on external morphology

1 Basal part of forewing with longitudinal and transverse black-margined silver-leaden striae........... N. conjugata sp. nov.

- Basal part of forewing just with longitudinal black-margined silver-leaden striae, arraged in three lines at basal 1/3, 1/2 and 2/3.......................................................................................... N. optima

Key to species of the optima group based on male genitalia

1 Valva narrow apically; apex of uncus distinctly truncated ventrally; anterior part of suspensorium far beyond posterior margin of vinculum in ventral view; vesica of aedeagus without slender cornutus dorsolaterally............. N. conjugata sp. nov.

- Apex of uncus curved ventrally; valva with distinct broad apex; anterior part of suspensorium at the same level of posterior margin of vinculum in ventral view; vesica of aedeagus with a pair of slender cornuti dorsolaterally............. N. optima