Mesocriconema ornicauda n. sp. and Ogma floridense n. sp. are described from two native habitats of central and northwestern Florida. Mesocriconema ornicauda is closest to M. annulatiforme (De Grisse &Loof, 1967) Loof &De Grisse, 1989, but differs by the shorter stylet of the female (43-50 vs. 54-65 mum) and the moderately conoid tail of the male, which is pointed in M. annulatiforme. Ogma floridense is closest to O. hungaricum (Andrassy, 1972) Siddiqi, 1986. Females differ from those of O. hungaricum by the first of two labial annuli being wider, whereas they are subequal in O. hungaricum. Ogma floridense females differ also by entire or bifid cuticular scales, which are consistently divided into two or four projections in O. hungaricum, the shorter body (360-471 vs. 480-550 mum), the shorter stylet (87-98 vs. 95-100 mum), and the more anteriorly located excretory pore (Rex = 17-19 vs. 21-23).
Keywords: Florida; M. ornicauda; Mesocriconema annulatiforme; O. hungaricum; Ogma floridense; morphology; new species; ring nematode; scanning electron microscopy (SEM); taxonomy.