RHABDITINAE 45 



present. Spicules two, slender, tapering, ending in minute 

 " buttons," and with four slender supporting rods towards 

 their distal ends. A strong, straight accessory piece present. 

 Testis single, not reflexed. Vulva prominent, at about the 

 middle of the body. Ovaries opposed, reflexed. 



Hab. Intestine of a Cricket (Gryllus). 

 Genotype : C. microbivorum Cobb, 1920. 



Cobb, 1920, Contr. Sci. Nematol., ix, 270 and key. 



16. Lepidonema Cobb, 1898. 



Cuticle, at least in anterior region, bearing longitudinal 

 rows of scales. Head narrower than neck. Lips obscure. 

 A very short buccal capsule present. Oesophagus club- 

 shaped, with a distinct pyriform posterior bulb. Tail of male 

 short, conical, ending in a short spike, and with a pair of large 

 postanal papillae near the tip. A pair of small preanal 

 papillae present. Spicules paired (?), short. Accessory piece 

 apparently absent. Tail of female conical, with bifurcated 

 tip. Vulva a little behind the middle of the body. Uterine 

 branches opposed. Ovaries reflexed. 



Hab. " In the larva of an insect " (one species known). 

 Genotype : L. bifurcata Cobb, 1898. 



Cobb, 1898, Agric. Gaz. N.S.W., Sydney, ix, 315. 



The only description available is contained in Cobb's fig. 36, 

 with its legend and formula. 



17. Hystrignathus Leidy, 1850. 



Syn. Xyo Cobb, 1898. 



Anterior region of body bearing transverse rows of simple, 

 backwardly directed spines or scales. Mouth on the summit 

 of a large, naked cone. Oesophagus long, cylindrical, ending 

 in a distinct pyriform posterior bulb with a narrow neck. 

 There is apparently a short pharynx, narrower behind, and 

 with longitudinal supporting rods. Male unknown. Tail of 

 female tapering. Vulva slightly behind middle of body. 

 Uterine branches opposed. Ovaries reflexed. Eggs oval. 



Hab. Intestine of Beetles (Passalus). 

 Genotjrpe : H. rigidus Leidy, 1850. 



Leidy, 1850, Proc. Acad. Nat. Sci. Philadelphia, v, 102 ; 

 1853, Smithsonian Contr. Knowl., Washington, v, 44; Cobb, 

 1898, Agric. Gaz. N.S.W., Sydney, ix, 315; Johnston, 1913, 

 Proc. R. Soc. Queensland, Brisbane (1912), 75. 



18. Heth Cobb, 1898. 



Head narrower than body, separated from it by a constric- 

 ij tion, and provided externally with four submedian double 



