Nineteen species of Colymbetinae, excluding Agabini, were collected in Wisconsin over the past 30 years. Included are three species of Colymbetes, two species of Copelatus, three species of Coptotomus, two species of Matus, two species of Neoscutopterus, and seven species of Rhantus. Species keys are provided for adults, but larvae are poorly known and species keys are provided only for larvae of Matus and Neoscutopterus. Information on distribution and abundance in Wisconsin, habitat, life cycle, and identification is provided for each species based on a study of 9,857 adults and 834 larvae. Most species had univoltine life cycles, with adults overwintering and larvae developing mostly in spring and early summer. A partial late summer generation occurred occasionally in some species of Coptotomus, Matus, and Rhantus. Adults overwintered in aquatic habitats, except those of five species of Rhantus that overwintered in terrestrial sites. Both species of Neoscutopterus had semivoltine life cycles, with adults and larvae overwintering.
Hilsenhoff, William L.
"Dytiscidae and Noteridae of Wisconsin (Coleoptera). III. Distribution, Habitat, Life Cycle, and Identification of Species of Colymbetinae, Except Agabini,"
The Great Lakes Entomologist, vol 26
Available at: https://scholar.valpo.edu/tgle/vol26/iss2/5