Cissidium, Motschulsky, 1855

Darby, Michael, 2020, A revision of Cissidium Motschulsky (Coleoptera: Ptiliidae) with seventy seven new species, European Journal of Taxonomy 622, pp. 1-188 : 169-170

Key to species group 5

1. Pronotal sides rounded....................................................................................................................... 2

– Pronotal sides angulate ...................................................................................................................... 4

2. Pronotum base with a linear row of ten foveae in two pairs of five each, the medial two pairs being larger than the outer three pairs ......................................................................... C. modestum sp. nov.

– Foveae along pronotal base of the same size, more randomly arranged ........................................... 3

3. Pronotum base with ± seven foveae ...................................................................... C. upiense sp. nov.

– Pronotum base with ± ten foveae.................................................................... C. sakaii Sawada, 2008 4. Head without a linear depression between the eyes .......................................................................... 5

– Head with a linear depression between the eyes ............................................... C. fraternum sp. nov.

5. Sides of mid-keel straight .................................................................... C. kolombangaricum sp. nov.

– Sides of mid-keel concave ................................................................................................................ 6

6. Mid-keel short, anterior angles very wide .................................................. C. brachypterum sp. nov.

– Mid keel anterior angles narrower..................................................................................................... 7

7. Mid keel shorter and wider .............................................................................. C. waginicum sp. nov.

– Mid keel narrower................................................................................................. C. apterum sp. nov.