OXYURINAE 27 



Leidy, 1849, Proc. Acad. Nat. Sci., Philadelphia, iv, 230 

 and 1850, v, 100; 1853, Smithsonian Contr. Knowl., Wash- 

 ington, V, 45; Hammerschmidt, 1838, Isis (Oken), Leipzig, 

 354 {Oxyuris diesingi) ; 1847, Naturw. Abhandl., Wien, i, 284 

 {Oxyuris blattae-orientalis, e. p.) ; Galeb, 1878, Arch. Zool. 

 exp. et gen., Paris, vii, 293 {Oxyuris diesingi, not 0. blattae). 



Aorurus, as originally described by Leidy, consisted of the 

 two subgenera Streptostoma and Thelastoma. These he raised 

 later, no doubt rightly, to the rank of genera. In these 

 circumstances, Streptostoma becomes a synonym of Aorurus. 



12. Thelastoma Leidy, 1849. 



Cuticle coarsely striated. Lateral alae present. Mouth 

 small, mthout apparent lips. A short pharynx apparently 

 present. Oesophagus proper club-shaped, followed by a 

 distinct pyriform bulb. Intestine may be provided near its 

 origin with a posteriorly-directed caecum. Male unknown.* 

 Tail of female long, subulate. Vulva in the posterior half of 

 the bodj'. Uterine branches and ovaries apparently opposed. 

 Eggs flattened on one side. 



Hab. Intestine of Myriopoda, Coleoptera and Orthoptera. 

 Genotype : T. attenuatum Leidy, 1849. 



Hammerschmidt, 1847, Naturw. Abhandl., Wien, i, 284 

 (Oxyuris blattae-orientalis, e. p.); Leidy, 1849, Proc. Acad. 

 Nat. Sci., Philadelphia, iv, 231 ; 1853, Smithsonian Contr. 

 Knowl., Washington, v, 46; Galeb, 1878, Arch. Zool. exp. et 

 gen., Paris, vi, 292 {Oxyuris blattae). 



Although the characters given by Leidy and others are 

 sufiicient to distinguish Thelastoma from Aorurus, they cannot 

 be said to furnish a satisfactory diagnosis, in the absence of a 

 fuller description of the genotype. 



13. Pseudonymus Diesing, 1857. 



Syn. Ptychocejjhalus Diesing, 1861 ; Helicothrix Galeb, 

 1878. 



Cuticle of neck with a series of annular swellings of different 

 sizes. Mouth with six lips. Oesophagus club-shaped, con- 

 taining six longitudinal chitinoid rodlets, and with a distinct 

 pyriform posterior bulb. Tail of male rounded, with a trun- 

 cate appendage bearing a ventrally-curved terminal spike. 

 One pair of postanal and two pairs and one median preanal 



* Leidy (1853), in his definition of the genus, states that there is a 

 single spicule in the male. No males appear to have been described for 

 any of the species assigned to this genus, although Galeb (1878) states 

 that in Oxyuris blattae ( = T. appendiculatum Leidy) the male is without 

 the intestinal caecum possessed by the female. It seems likely that 

 the form in question belonged to a different species. 



