Hydraena (Hydraenopsis)

PERKINS, PHILIP D., 2014, A revision of the water beetle genus Hydraena Kugelann for southern Africa (Coleoptera: Hydraenidae), Zootaxa 3758 (1), pp. 1-92 : 6

Hydraena (Hydraenopsis) : Cooperi Group

Five species are placed in this group. Members are very small to small (ca. 1.17–1.69 mm) and are very similar in dorsal habitus, with only H. reflectiva standing out due to its very smooth and finely punctate dorsum. The ventral characters are also very similar in the species, and the males do not have diagnostic sexual dimorphisms. The aedeagus ( Figs. 4, 5 , 8, 9 , 37 ), which must be examined for reliable determinations, is small to extremely small, and has the distal half bent at an angle to the main piece; the short parameres are inserted near or at the bend. The small size of the aedeagus, its unusual architecture, and the external similarity of the species makes the Cooperi Group one of the most difficult.

Figures

FIGURES 4–5. Aedeagi of holotypes of H. cooperi and H. cooperoides, and aedeagal variants of H. cooperi.

FIGURES 8–9. Aedeagi of holotypes.

FIGURES 36–37. Aedeagi of holotypes.