ISOPODS OF NORTH AMEEICA. 



557 



PROBOPYRUS BITHYNIS Richardson. 



Proboptjrux bithynis RICHARDSON, Pror. U. S. Nat. Mus., XXVII, 1904, pp. 68-70. 



Localities. Mississippi River near the exposition grounds in New 

 Orleans, Louisiana, on Bithynis ohionis (Smith); Escondido River, 



FIG. 606. PROBOPYRUS BITHYNIS. a, DORSAL VIEW OF FEMALE. 6, VENTRAL VIEW OF SAME, x 16 



Nicaragua, 50 miles from Bluefields, on Bithynis acanthurus (Wieg- 

 mann). 



Body of female with dorsal surface perfectly white, having only 

 three small patches of black on one side at the post-lateral parts of the 

 second, third, and fourth thoracic segments. Ventral side of the body 

 with the first pair of incubatory lamellse 

 almost entirely covered with patches of 

 black, and with all the other lamellae of 

 one side having patches of black, those 

 of the other side being without these 

 patches, with the exception in some speci- 

 mens of the second lamella. Patches 

 of black also present on the ventral side 

 of the lateral margins of the second, 

 third, and fourth thoracic segments of 

 one side the same side on which these 

 markings occur on the dorsal surface and 

 to which the incubatory lamellee, likewise marked with patches, are 

 attached. Legs of both sides white and without any markings. 



Head with the antero-lateral corners produced into prominent pro- 

 cesses; anterior margin between these processes straight; posterior 

 margin narrowly rounded. Length of head about equal to its breadth. 

 E}^es wanting. 



The thoracic segments are distinctly defined. Ovarian bosses are 

 present on all the segments, occupying only the anterior portion of 

 the sublateral margin of the first four segments. The epimera are 



FIG. 607. PROBOPYRUS BITHYNIS. 

 FIRST LAMELLA OF MARSUPIUM, 

 RIGHT SIDE. X 10. 



