Distribution China, mostly eastern regions between Hainan and the province of Jiangxi and a western location Chongquing province. Current records are likely to underpresent the diversity and distribution of this genus and Li & Wei (2014) predict a more extensive range in China based on climatic correlations.
Systematics Monophyly of Napialus supported by unique configuration of the male genitalia, noteably the large pseudoteguminal process (Li & Wei, 2014). Napialus kulingi was transferred from Hepialiscus by Nielsen et al. (2000), but there is no supporting evidence and the species was not inlcuded in Napialus by Li & Wei (2014). The external appearance is more like that of other Hepialiscus and for the present the position of kulingi requires detailed examination of the type. Wing venation of of Napialus is of the oxycanine form, suggesting that this genus may belong to an Old World 'oxycanine' clade. Napialus may represent a largely northeastern vicariant of the 'oxycanine' genus Hepialiscus (Grehan, 2011).
Habitat Forest (for Napialus spinosus (Li & Wei, 2014).