102 BULLETIN 51, UNITED STATES NATIONAL MUSEUM. 



P. 1068. The classification and geographical distribution of the pearly 

 fresh-water mussels. By Charles T. Simpson. 



pp. 29r5-343, 1 plate. 



P. 1069. Note on the occu;"rence of an armadillo of the genus Xenurus 

 in Honduras. By Frederick W. True. 



pp. 346-347, 2 pis. 



P. 1070. The genu's Callineotes. By Mary J. Rathbun. 



pp. 349-375, 17 pis. 



P. 1071. Descriptions of two new species of fresh-water crabs from 

 Costa Rica. By Mary J. Rathbun. 



pp. 377-379, 2 pis., 3 flgs. 



P. 1072. Description of four new triassic unios from the staked plains 

 of Texas. By Charles T. Simpson. 



pp. 381-385, 5 flgs. 



P. 1073. Revision of the North American Empidse — a family of two- 

 winged insects. By D. W. Coquillett. 



pp. 387-440. 



B. 1074. Description of a new subspecies of the genus Peuced/rcmius 

 Coues. By Robert Ridgway. 



p. 441. 



P. 1075. Preliminary diagnoses of new mammals from the Mexican 

 boundary of the United States. By Edgar A. Mearns. 



pp. 443-447. 



P. 1076. Characters of a new American family of passerine birds. By 

 Robert Ridgway. 



pp. 449-460. 



P. 1077. Osteological and pterylographical characters of the Procnia- 

 tidse. By Frederic A. Lucas. 



p. 505-607, 5 flgs. 



P. 1078. 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 nev species of Oyanecula. 

 By Charles W. Richmond. 



pp. 451-603. 



P. 1079. 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. 



P. 1080. Descriptions of two new subspecies of the downy woodpecker, 

 Dryobates pubescens Linnaeus. By Harry C. Oberholser. 



pp. 547-550. 



P. 1081. 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. 



