COBB: A KEY TO THE GENERA OF FREE-LIVING NEMAS 459 



Spear-guide smaller, slighter, not forming cuirasse; bursa present 



Nema cephalated by constriction, head idiscoid; spear long; bursa loba.te....Dolichodorus Cobb 1914 

 Nema cephalated by contraction or not at all ; bursa not lobate 

 Anterior end extensible.narrow & beak-like,inner framework cuticular. . Tylenchorhynchus Cobb 1913 



Anterior end never narrowed & beak-like, without cuticular framework Tylenchus Bast. 1865 



Gonads 9 reflexed (for alternative see preceding page) 

 Structure of pharynx obscure; oesophagus with cardiac swelling only 



"Spear" 3 rods, ant. hinged to 2 U-shaped pieces, post. 2 stalked swellings. . (Tylopharynx de Man 1876) 

 "Spear" rods 2-3, base heavy, irreg.; setae or papill.; ovary obscure. . . Diphtherophora de Man 1880 



( = Chaolaimus Cobb 1893 

 = Archionchus Cobb 1913) 

 Structure of pharynx obvious 



Oesophagus without median bulb, cardiac bulb present 

 Cardiac swelling cylindroid (i.e. oesophagus dorylaimoid) 

 Oral spear large, over 5%, base 3-bulbed but not trif urcate 



. large, over 5%, base 3-bulbed but not trif urcate Xiphinema Cobb 1913 



Oral spear smaller, under 5%, base trif urcate (Tylencholaimus de Man 1876) 



Cardiac swelling pyriform to clavate 



Spear 3-bulbed at base, stout; amphid protrusile, tube cuticularized Triplonchium Cobb 1920 



Spear 3-pronged; amph. J head-width, transverse-oval; labial papillae 6 Tylolaimophorus de Man 1880 

 Oesophagus with median bulb, often with cardiac swelling also 



Body thick, not serpentine; 9 and larval forms Heterodera Schmidt 1871 



( = Meloidogyne Goldi 1887 

 = Caconema Cobb 1924) 

 Body serpentine 



Junction oesoph.& intestine indef . ;annules plain;tail rounded, with bursa. . (Hoplolaimus Daday 1905) 

 Junction oesoph. & intestine definite; bursa none; tf and larval forms 

 Spear really the apophyses of 3 movable onchia at base anterior pharynx Tylenchodon Fuchs 1930 



Spear tylenchoid Heterodera Schmidt 1871 



( = Mdoidogyne Goldi 1887 

 = Caconema Cobb 1924) 

 Ovary 1 (for alternative see preceding page) 

 Gonad 9 reflexed; setae 



Spear trif urcate half its length, base swollen; oesoph. with cardiac bulb only. .Dory Ilium Cobb 1920 

 Spear furcate at base only; bulbs usually 3 

 Body thick, inert; parasitic 9 forms 



Nema body swollen, head and neck narrow; vulva 90%; in citrus roots Tylenchulus Cobb 1913 



Nema sausage-shaped ;organs degenerated exc.gonads; vulva term.; in insects Allantonema Leuck. 1884 



( = Tylenchomarphus Fuchs 1914) 

 Body islender or serpentine 

 Oral spear vestigial; median bulb ireduced; cf and larval forms 



Habitat in citrus roots and soil Tylenchulus Cobb 1913 



Habitat in and around wood-boring beetles Allantonema Leuck. 1884 



(=Tylenchomorphus Fuchs 1914) 

 Oral spear well developed 

 Median oesophageal bulb elongate; vulva over 70%, ovary anterior; bursa none 



Spear 3-4%; annules 0; median bulb ireduced; anus not functional Tylenchulus Cobb 1913 



Spear 8-23%;annules under 150,retrorse;median bulb oft valvate;vulva 70-95%. .Ogma Southern 1914 



(=Iota Cobb 1913) 

 Median oesophageal bulb absent 



"Spear" rods 2-3, base heavy, irreg.; setae or papilloid; vulva 5Q%... Diphtherophora de Man 1880 



( = Chaolaimus Cobb 1893 

 = Archionchus Cobb 1913) 



"Spear" of usual structure, shaft distinct, base tripartite 



Tip of spear tapering, posterior prongs little swollen; vulva 33-72%. . Tylencholaimus de Man 1876 

 Tip of spear (dorso-ventral view) arrow-headed; vulva 25%, ovary post. Pharetrolaimus de Man 1921 

 Gonad 9 outstretched 



Habitat marine;"spear" an evertible pharyng. lining ;amph. round ;neck 4% Siphonolaimus de Man 1893 

 Habitat not marine; median oesophageal bulb present (Neotylenchus ?) 



Cephalic setae 4, li head-widths long; longitudinal striae 10; in cranberry bog. .Atylenchus Cobb 1913 

 Cephalic setae 



Dorsal oes.gland emptying at med.bulb;junct.oes.&intest. indef. ;bursa A phelenchoides Fischer 1894 



( = Seinura Fuchs 1931 



=Parasitaphelenchus Fuchs 1930 



= Pathoaphelenchus (Cobb) Steiner 1931) 



Dorsal oes. gland emptying at base of spear; genera tylenchoid 



Spear under 5%; junction oesoph. & intest. usually definite; nema under 5% wide; bursa present 

 Anterior oesoph. with median bulb; head of 6 sectors; tail without mucron. ...Tylenchus Bast. 1865 

 Anterior oesoph. fusiform to isthmus; median bulb not definite; in or about plants 



Habitat crop plants; head of 8 sectors; terminus of tail straight Neotylenchus Steiner 1931 



Habitat bladders of Fucus, &am'g marine algae;head of 6 sectors ; tail hooked Halenchus Cobb 1933 

 Spear 8-24%; oesoph. lining flexible, looping; nema 5%+ wide; bursa 0; vulva 72-94% 

 Base of spear bulbed, not fluked; annules over 100, not retrorse; junct. oes. & intest. definite 



Oral area not raised; annulation fine Paratylenchus Micol. 1922 



Oral area raised, surrounded by "fossa" ; annulation rather coarse Procriconema Micol. 1925 



Base of spear anchor-shaped (fluked); annules under 150, retrorse; junct. oes. & intest. indef. 



Scales, prickles and fringes absent from annules Criconema Hoff manner & Menzel 1914 



Scales, prickles or fringes ornamenting the annules Ogma Southern 1914 



(=Iota Cobb 1913) 



