TiENIOTD CESTODES OF NORTH AMERICAN BIRDS. 89 



Genus STILESIA Raiiliet, 1898. 



Generic diagnosis. — ( ? ) Paruterininse : Head unarmed, without 

 rostellum. Neck present. Segments broader than long. A dou- 

 ble set of reproductive organs in each segment, with opposite pores, 

 or with irregularly alternating pores, those of one side, with the cor- 

 responding cirrus pouch, vagina and ovary having been suppressed, 

 both of which conditions may occur in the same strobila. Genital 

 canals pass between the longitudinal excretory vessels and dorsal 

 of the nerve. Dorsal excretory vessePa considerable distance mediad 

 from the ventral vessel. Testicles relatively few (6 to 12 in each set) 

 in the lateral portions of the segment in the neighborhood of the lon- 

 gitudinal excretory vessels. Ovary small, globose, between the 

 dorsal and ventral excretory vessel on pore side of segment. Yolk 

 gland not apparent. Uterus small, spherical, sac-like, one in each 

 lateral half of the segment between the dorsal and ventral excretory 

 vessels. . When the ovary is absent from one side, eggs from the op- 

 posite side of the segment appear to pass across through the median 

 field in a manner not understood and enter the uterus of the side in 

 which the ovary is lacking. Immediately anterior and mediad of 

 each uterus a para-uterine organ develops into which the eggs prob- 

 ably pass. Eggs with two envelopes. Adults in mammals (rumi- 

 nants) . 



Type-species. — Stilesia globipunctata (Rivolta, 1874) Raiiliet, 1893. 



Siabfaixiily H'X'IVIEN^OIjISPIDIJS'^ze; (emencied n.am.e). 



Hymenolepinse Perrier, 1897. 



Family diagnosis. — Hymenolepididse : Rostellum armed with a 

 single crown of hooks, or more rarely rudimentary and unarmed. 

 Segments always broader than long. Longitudinal muscles in two 

 layers. A single set of reproductive organs in each segment. Genital 

 pores unilateral. Genital canals pass on the dorsal side of the lon- 

 gitudinal excretory vessels and nerve. Testicles one to four. Vas 

 deferens always short with seminal vesicle. Uterus persistent, sac- 

 like. Egg with three transparent shells. Adults in mammals and 

 birds. 



Type-genus. — Hymenolepis Weinland, 1858. 



Genus OLIGORCHIS Fuhrmann, 1906. 



Generic diagnosis. — Hymenolepidinas : Rostellum armed with a 

 single crown of hooks, four testicles in each segment. Seminal 

 vesicle and seminal receptacle large. Adults in birds. 



Type-species. — OligorcTiis strangulatus Fuhrmann, 1906. 



OLIGORCHIS STRANGULATUS Fuhrmann, 1906. 



For description see Fuhrmann, 1906a, pp. 217-218, figs. 26-30. 

 Host. — Elanoides forficatus . 



