Key to species of Mileewini from Hainan Island

1 Vertex with distinctive pattern consisting of three median pale ovals narrowly bordered with black (Fig. 2a); forewing with costal margin with a white patch divided by a black or red line (Fig. 2b) ( Ujna).................................... 2

- Vertex and forewing not as above ( Mileewa)................................................................ 3

2 Forewing with costal patches divided by red stripe (Fig. 2b); pygofer without ventral process......... U. cavipenis sp. nov.

- Forewing with costal patches divided by black stripe; pygofer with ventral process. See Dietrich et al., 2020; Yang et al., 2014, Fig. 7 for habitus........................................................................ U. consors Distant

3 Posterior part of mesonotum (scutellum) bright yellow. See Yang et al., 2014, Fig. 31 for habitus... M. margheritae Distant

- Posterior part of mesonotum (scutellum) brown or black...................................................... 4

4 Male subgenital plates with apical margin broad with big dentate process. See Yang et al., 2014, Fig. 41 for habitus.......................................................................................... M. shirozui (Ishihara)

- Male subgenital plates with apical margin without dentate process.............................................. 5

5 Forewing with white patch distally on costal margin, on middle of inner margin, and on base of second apical cell respectively. See Yang et al., 2014, Fig. 8 for habitus..................................................... M. alara Yang & Li

- Forewing not marked as above........................................................................... 6

6 Style S-shaped (Fig. 1h); aedeagus with a pair of flat basal processes............................................ 7

- Style and aedeagus not as above......................................................................... 8

7 Aedeagus with a pair of dentate apical processes. See Yang et al., 2014, Fig. 40 for habitus............... M. sharpa Yang

- Aedeagus with a lobe-like apical process (Figs 1 j–l)........................................... M. triloba sp. nov.

8 Apex of aedeagus without processes. See Yang et al., 2014, Fig. 38 for habitus.................... M. ponta Yang & Li

- Apex of aedeagus with processes......................................................................... 9

9 Apical aedeagal processes attaining midlength of aedeagus. See Yang et al., 2014, Fig. 26 for habitus.................................................................................................. M. lackstripa Yang & Li

- Apical aedeagal processes short and stout, distinctly not attaining midlength of aedeagus. See Yang et al., 2014, Fig. 48 for habitus............................................................................. M. zhangi Yang & Li