Key to species of the Chrysodema sonnerati species-group

1. Lateral impression on elytron does not exceed half the length of elytron.............. C. (C.) sonnerati Lap. & Gory, 1835

- Lateral impression on elytron obviously present on more than half the length of elytron.............................. 2

2. Punctation on each elytron always regular, forms 4 wide longitudinal intercostal intervals; a large elliptical principal impression protrudes from lateral impression to 3rd intercostal interval at apical third of each elytron; penis oval.................................................................................................. C. (C.) hainanensis sp. nov.

- Punctation on each elytron generally irregular or weakly regular; elytral lateral impression without any transverse extended impression; penis broadly-oval........................................................................... 3

3. Dorsum strongly shiny, green or green-purple; apices of parameres rounded.......... C. (C.) lewisii lewisii Saunders, 1873

- Dorsum semi-matt, usually dark blue; apices of parameres subtruncate, inner tip angular............................. ................................................................. C. (C.) lewisii nakatai Frank & Sekerka, 2020