Over 200 species of freshwater and terrestrial water bears (phylum Tardigrada) are known to occur in North America. Of these, 20 species have been recorded in Louisiana. Foliose and fruticose lichen and moss samples collected in 2011 in the city of Lake Charles and in Sam Houston Jones State Park, Calcasieu Parish, Louisiana, USA, were stored in paper envelopes and later soaked in tap water overnight. Tardigrade specimens and eggs were extracted and mounted in polyvinyl lactophenol. The samples contained a new species of tardigrade. Milnesium lagniappe sp. n. has claw formula [2–3]-[3–2] and 9 sculptured bands in the dorsal and lateral cuticle. The new species most closely resembles Milnesium reticulatum, a species known only from the Seychelles Islands, in its cuticular pattern. However, M. lagniappe sp. n. is almost twice as large as M. reticulatum, lacks gibbosities, has proportionally wider buccal tube and longer claws, and has a more posterior point of stylet insertion. Reexamination of tardigrades from central Florida, USA, previously reported as M. tardigradum shows that they are in fact M. lagniappe sp. n.