(after Andrássy, 2007)
| 1 | a | Cuticle thick, coarsely annulated, often with extensions, isthmus broad and amalgamated with basal bulb | 2 |
| b | Cuticle thin, finely annulated, without extensions, isthmus slender, not amalgamated with basal bulb | 3 | |
| 2 | a | Females and juveniles cigar-shaped; cuticular annules retrorse, often with extensions; male tail short, bursa small or absent | Criconematidae |
| b | Females and juveniles slender, vermiform; cuticular annules rounded; male tail long, bursa large | Hemicycliophoridae | |
| 3 | a | Mature female vermiform to elongate-obese; procorpus of esophagus wide; stylet may be long | Paratylenchidae |
| b | Mature female saccate or spherical; procorpus of esophagus slender; stylet short | 4 | |
| 4 | a | Mature female spherical, vulva terminal; excretory pore in anterior 25% of body | Sphaeronematidae |
| b | Mature female elongate-obese; vulva not terminal; excretory pore at >50% of body length | Tylenchulidae |
after Andrássy, 2007)
| 1 | a | Female with a cuticular sheath of rounded annules | Hemicriconemoides Chitwood & Birchfield, 1957 |
| b | Female without cuticular sheath | 2 | |
| 2 | a | Cuticular annules in females and juveniles with scales, spines or other extensions | 3 |
| b | Cuticular annules in females smooth, occasionally with extensions in juveniles | 9 | |
| 3 | a | Cephalic region small, knob-like | Blandicephalonema Mehta & Raski, 1971 |
| b | Cephalic region not knob-like, usually with two annules | 4 | |
| 4 | a | Each cuticular annule with continuous fringe of spines | Crossonema Mehta & Raski, 1971 |
| b | Extensions of cuticular annules separated, not fringe-like | 5 | |
| 5 | a | Cuticular extensions in alternating rows | Croserinema Khan, Chawla & Sala, 1976 |
| b | Cuticular extensions not alternating, arranged in longitudinal rows | 6 | |
| 6 | a | One large saucer-shaped cephalic annule | Paterocephalonema Mehta & Raski, 1971 |
| b | Two, sometimes three, moderately-sized cephalic annules | 7 | |
| 7 | a | Cuticular extensions transparent, membranous | Bakernema Wu, 1964 |
| b | Cuticular extensions not membranous | 8 | |
| 8 | a | Shape and size of cuticular extensions differ on dorsal and ventral sides | Orphreyus Siddiqi, 2000 |
| b | Shape and size of cuticular extensions similar on dorsal and ventral sides | Ogma Southern, 1914 | |
| 9 | a | Annules of juveniles with longitudinal rows of scales or spines; females with smmoth annules, except in tail region | 10 |
| b | Annules of both juveniles and females without scales or spines | 13 | |
| 10 | a | Scales and spines present on annules in posterior region of females | Neolobocriconema Mehta & Raski, 1971 |
| b | Scales and spines not present on annules in posterior region of females | 11 | |
| 11 | a | Cephalic region with submedial lobes | Lobocriconema De Grisse & Loof, 1965 |
| b | Cephalic region without submedial lobes | 12 | |
| 12 | a | Head with one dome-shaped annule; annules with encrustations | Amphisbaenema Orton Williams, 1982 |
| b | Head with two ring-like annules; annules without encrustations | Criconema Hofmänner & Menzel, 1914 | |
| 13 | a | Vulva open; cephalic region with submedial lobes | Mesocriconema Andrássy, 1965 |
| b | Vulva closed; cephalic region without submedial lobes | 14 | |
| 14 | a | Anterior cephalic annule disc-like, offset by a collar | Discocriconemella De Grisse & Loof, 1965 |
| b | Anterior cephalic annule not disc-like, not offset | 15 | |
| 15 | a | Stylet exceedingly long, flexible | Xenocriconemella De Grisse & Loof, 1965 |
| b | Stylet not exceedingly long, not flexible | 16 | |
| 16 | a | Anterior lip of vulva overhanging aperture | Nothocriconemoides Loof & De Grisse, 1971 |
| b | Anterior lip of vulva not overhanging aperture | Criconemoides Taylor, 1936 |
Andrássy, I. 2007. Free-living Nematodes of Hungary (Nematoda Errantia) Vol. II. Hungarian Natural History Museum. Budapest. Hungary, 496 pp.