588 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



1O2. Genus ETHELUM Budde-Lund. 



Antennae with the flagellum composed of two articles. Inner lobe 

 of the first or inner maxillae furnished with four plumose processes. 



First segment of the thorax with the epimeron thick, separated 

 above from the middle of the segment by a longitudinal furrow, lat- 

 eral margin not excavate, posteriorly cleft. The second segment of 

 the thorax with the epimera entire. 



Outer branches of all the pleopoda furnished with tracheae. 



ANALYTICAL, KEY TO THE SPECIES OF THE GENUS ETHELUM. 



a. Surface of body smooth, with the side parts of the thoracic segments (two to seven) 



and the abdominal segments not bent downward. 



b. Prosepistoma plain. Coxopodite of the second segment of the thorax forming a 

 nearly inconspicuous ridge before the leg. Caudal segment triangular; apex 

 pointed. Inner branch of the uropoda extends beyond the apex of the caudal 



segment Ethelum modestum (Dollfus) 



b f . Prosepistoma with a shield-like convexity. Coxopodite of the second segment 

 of the thorax hardly visible, only a very small dentiform process before the 

 leg. Caudal segment flat, with rounded apex. Inner branch of the uropoda 

 reaches two-thirds the length of the caudal segment. 



Ethelum americanum (Dollfus) 



a'. Surface of body slightly granulated, with the side parts of the thoracic segments 

 (two to seven) and the abdominal segments bent downward. Caudal segment 

 with blunt rounded apex. Inner branch of the uropoda reaches two-thirds the 

 length of the caudal segment Ethelum reflexum ( Dollfus) 



ETHELUM MODESTUM (Dollfus). 



Mesarmadillo modestus DOLLFUS, Proc. Zool. Soc. London, 1896, p. 397. RICH- 

 ARDSON, Proc. U. S. Nat. Mus., XXIII, 1901, p. 573. 



Ethelum modestum BUDDE-LUND, A Revision of "Crustacea Isopoda Terrestria," 

 1899, p. 25; Ent. Meddel. (2), I, Pt. 2, 1899, p. 91. 



Locality. St. Vincent, West Indies. Dry forest, leeward, under a 

 log, 800 feet. 



"Body rather convex and narrow, smooth. Prosepistoma plain, 

 continuous with the forehead in the middle, and separated from it on 

 both sides by a transverse, incomplete, preocular cut. Eyes moderate; 

 ocelli about 16. Antennae short, flagellum very small, first joint three 

 times shorter than the second. Pereion: first segment with the antero- 

 median tubercle hardly perceivable; coxopodites distinct on the entire 

 length of the edge of the segment, with the hind part diverging and 

 covered by the posterior angle of the segment. Coxopodite of the 

 second segment forming a nearly inconspicuous ridge before the leg. 

 Pleon, telson: pleotelson triangular; sides feebly curved; apex pointed. 



See Budde-Lund for characters of genus, A revision of Crustacea Isopoda Ter- 

 restria, 1899, Pt. 1, Eubelurn, p. 24. 



