Key to large males of Prosopocoilus gracilis (Saunders) and its allied species from China.

1. Mandible curved strongly, longer than the total length of head and pronotum…….….................................................................………2

Mandible almost straight, no longer than the total length of head and pronotum......................................................................................4

2. Mandible with a sub-apical tooth near the apex.….….……...…..…..……….……......................................................................……...3 Mandible without a sub-apical tooth near the apex………………………..............................................................………….... P. gracilis

3. A large tooth close to basal edge of mandible....................................................................................................................... P. piceipennis

A large tooth close to front edge of mandible.....................................................….…..............................................................… P. similis

4. The basal tooth rectangle, the apex bifurcated; the tooth on the ventral margin of paramere long and sharp...................... P. crenulidens

The basal tooth triangular, the apex sharp; the tooth on the ventral margin of paramere short and expanded…….....…... P.denticulatus