Abstract snippets:

A key is provided for the nine known species of North American Liodessus Guignot. The genus Liodessus is diagnosed, and its taxonomic history and questionable status as a natural group are discussed.

Male genitalia are the only consistently useful structures known for differentiating [the four] species in the L. affinis complex. Females are not distinguishable based on currently known morphological features but may be identified using geographic information. Characters used previously, including coloration, punctation and general shape are too variable within and between species to be useful for species diagnosis or delimitation.

Miller, K.B. 1998. Revision of the Nearctic Liodessus affinis (Say 1823) species group (Coleoptera: Dytiscidae, Hydroporinae, Bidessini). Entomologica Scandinavica 29(3): 281-314.