This is the third in a series providing distributional and biological notes on blister beetles (Meloidae) in North and Central America. This paper covers 45 species in the U.S.A., Canada, Guyana, and Mexico in the genera Epicauta Dejean, 1834, Gnathium Kirby, 1818, Linsleya MacSwain, 1951, Lytta Fabricius, 1875, Megetra LeConte, 1859, Meloe Linnaeus, 1758, Phodaga LeConte, 1858, Pseudozonitis Dillon, 1952, Spastonyx Selander, 1954, Tetranoyx Latreille, 1805, and Zonitis Fabricius, 1775. These records include three new country records, 12 new state/provincial records, seven new host records, and numerous range extensions.