102 [Oct. 



Ovum oval, l-308th inch Ions by 1-500^ inch broad. 



Habitation. Found in the intestine, in numbers of from one to three, in the 

 larva of a lameliicorn insect. 



Remar/c. The descriptions of the above are entirely taken from females, con- 

 siderable numbers of which I have found and possess, but I have never yet been 

 able to discover a single male. 



5. OxYURis sociALis. Body vs^hite, narrow, cylindrical, elastic, posteriorly 

 attenuated; mouth projecting, with a short pharynx; oesophagus consisting of 

 two portions : first portion long, cylindrical, dilated at its posterior part ; secona 

 portion, narrow, pyriform ; ventriculus moderately dilated at commencement, 

 capacious, cylindrical ; tail long, narrow, acute. 



Female. From 1 line to 2 and l-5th lines in length ; breadth l-266th inch- 

 First portion of oesophagus l-66th inch long, l-800th inch broad; second portion 

 l-200th inch long by l-6C6lh inch broad. Generative aperture projecting, just 

 anterior to middle. Tail simple pointed, l-57th inch long from anus, l-400th 

 inch broad at base. 



Ovum oval, white, l-363d inch long, l-C6Gth inch broad. 



Male. Length 4-5ths to 3-5ths of a line ; breadth l-400th inch ; posteriorly 

 recurved. Tail pointed, furnished with five minute epidermoid prominences on 

 the inner side, l-133d inch long from anus. Spiculum of penis single, simple, 

 curved, l-400th inch long. 



Habitation. Found in numbers of from five to twenty, of which one-fifth are 

 males, in the large intestine of the large black cricket (Acheta abbreviata.) 



Genus Hy strignatlius . Body cylindrical, anteriorly furnished with transverse 

 rows of simple spines projecting backward ; mouth surmounting a largejnaked pa- 

 pilla; oesophagus of two portions: the first long, cylindrical, the second short and 

 pyriform; annulations indistinct posteriorly ; tail long. 



6. Hystrignathus rigidus. Body straight, rigid, cylindrical, narrowed 

 anteriorly and posteriorly ; anteriorly furnished with 106 transverse rows of 

 simple spines projecting obliquely backward, each row corresponding to an annu- 

 lation and containing about sixteen spines ; anterior spines longest, equal to the 

 width of the annulations, becoming shorter posteriorly and decreasing to mere 

 points. First annulation of the mouth truncated, conical, smooth ; second annu- 

 lation smooth. Pharynx extending through the first two annulations. First 

 portion of oesophagus long, cylindrical ; second portion with a narrow cylindri- 

 cal neck and globular body ; ventriculus cylindrical, slightly dilated anteriorly, 

 narrowed anteriorly ; rectum elongated conical. Tail long, curved. Generative 

 aperture very near the middle of the body. 



Length 2 lines; greatest breadth l-140th inch; tail l-40th inch long from 

 anus, 1-lOOOth inch broad at middle ; anterior or spinous portion of body l-2Gth 

 inch long or one fourth of the whole length. First portion of cesophagus l-50th 

 inch long, l-520th inch broad ; second portion l-190th inch long, l-320th inch 

 broad at body. Anterior spines l-2000th inch long. Fifty-eight spinous annula- 

 tions corresponding to the first portion of the cesophagus, twelve to the second 

 portion. Annuli posteriorly indistinct. 



Ova oval, l-214th inch long, by 1-545 inch broad. 



Habitation. The female only I have found in numbers of one to five within, 

 and adhering by the mouth to the parietes of, the ventriculus of Passaluscornutus. 



