Revision of Macrelmis Motschulsky, 1860 in the Southwestern United States and Northern Mexico with description of four new species (Coleoptera: Elmidae: Elminae).

Describes four new species, three of which are found in the United States: Macrelmis harleyi, found in extreme SE Arizona; Macrelmis shepardi, found in AZ and NM; and Macrelmis texangusta, found in TX. This brings the total of species found in the United States to six. Provides an updated key to species found in the USA and Mexico.