. L069. 
SHOT: 
LOE. 
. 1072. 
- LOT: 
101. 
. L075. 
SA076; 
OTE 
. L078. 
pe LOWas 
. LO80. 
OBA 
BULLETIN 51, UNITED STATES NATIONAL MUSEUM. 
. The classification and geographical distribution of the pearly 
fresh-water mussels. By Charles 'T. Simpson. 
pp. 295-343, 1 plate. 
Note on the occurrence of an armadillo of the genus Xenurus 
in Honduras. By Frederick W. True. 
pp. 345-347, 2 pls. 
The genus Callinectes. By Mary J. Rathbun. 
pp. 349-875, 17 pls. 
Descriptions of two new species of fresh-water crabs from 
Costa Rica. By Mary J. Rathbun. 
pp. 377-879, 2 pls., 3 figs. 
Description of four new triassic unios from the staked plains 
of Texas. By Charles T. Simpson. 
pp. 381-385, 5 figs. 
Revision of the North American Empidee—a family of two- 
winged insects. By D. W. Coquillett. 
pp. 387-440. 
Description of a new subspecies of the gerus Peucedramus 
Coues. By Robert Ridgway. 
p. 441. 
Preliminary diagnoses of new mammals from the Mexican 
boundary of the United States. By Edgar A. Mearns. 
pp. 443-47. 
Characters of a new American family of passerine birds. By 
Robert Ridgway. 
pp. 449-450. 
Osteological and pterylographical characters of the Procnia- 
tide. By Frederic A. Lucas. 
p. 505-507, 5 figs. 
Catalogue of a collection of birds made by Dr. W. L. Abbott 
in Kashmir, Baltistan and Ladak, with notes on some of the 
species, and a description of a new species of Cyanecula. 
By Charles W. Richmond. 
pp. 451-508. 
On birds collected by Dr. W. L. Abbott in the Seychelles, 
Amirantes, Gloriosa, Assumption, Aldabra, and adjacent 
islands, with notes on habits, etc., by the collector. By 
Robert Ridgway. 
pp. 509-546. 
Descriptions of two new subspecies of the downy woodpecker, 
Dryobates pubescens Linneus. By Harry C. Oberholser. 
pp. 547-550. 
Preliminary description of a new subgenus and six new spe- 
cies and subspecies of hares, from the Mexican border of the 
United States. By Edgar A. Mearns. 
pp. 551-565. 
