CONTENTS OF VOL. XI. 



PAGE 



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ARTICLE I. (No. 230.) Arrangement of the Families of Mammals ; 

 with Analytical Tables. Prepared for the Smith- 

 sonian Institution by Theodore Gill, M.D., Ph.D. 

 November, 1872. Pp. 104. 



ARTICLE II. (No. 247.) Arrangement of the Families of Fishes, 

 or Classes Pisces, Marsipobranchii, and Leptocar- 

 dii. Prepared for the Smithsonian Institution by 

 Theodore Gill, M.D., Ph.D. Nov. 1872. Pp. 96. 



ARTICLE III. (No. 256.) Monographs of the Diptera of North 

 America. Part III. Prepared for the Smithsonian 

 Institution by H. Loew. December, 1873. Four 

 plates. Pp. 376. 



ARTICLE IV. (No. 261.) Directions for Collecting and Preserv- 

 ing Insects. Prepared for the use of the Smith- 

 sonian Institution by A. S. Packard, Jr., M.D. 

 September, 1873. Pp. 60. 



ARTICLE V. (No. 264.) New Species of North American Cole- 

 optera. Prepared for the Smithsonian Institution 

 by John L. Le Coxte, M.D. Part II. May — June, 

 1873. Pp. 74. 



ARTICLE VI. (No. 265.) Classification of the! Coleoptera of North 

 America. Prepared for the Smithsonian Institution 

 by John L. Le Conte, M.D. Part II. May — June, 

 1873. Pp. 72. 



