Key to species of Longtania (male)

1 Aedeagus nearly straight in lateral view, with reflexed spine subapically, medially with 3 spines; outer angle of paramere triangularly produced laterad in caudal view ............................................................................ L. picea Ding

- Aedeagus curved dorsad in lateral view (Figs 9, 11, 12), lacking reflexed spine subapically, submedially with 4 spines (Fig. 11); outer angle of paramere roundly produced laterad in caudal view (Fig. 15) .......... L. arcuata sp.nov.