Key to males of Indosialis

1. Male ninth gonostylus robust (Figs. 5, 9); male tenth sternum with distal lobes directed straight posteriad (Figs. 6, 10).................................................................................................................................................. 2

- Male ninth gonostylus slender (Fig. 13); male tenth sternum with distal lobes curved ventrolaterally (Fig. 14)........................................................................................................................ Indosialis minora (Banks)

2. Male ninth gonostylus with distal half narrowed (Fig. 7); male tenth tergum subtriangular with blunt tip (Fig. 7) ..................................................................................... Indosialis bannaensis Liu, Yang & Hayashi

- Male ninth gonostylus with distal half inflated (Fig. 11); male tenth tergum with distal half narrowed into a digitiform process (Fig. 11) .............................................................................. Indosialis indicus sp. nov.