IX 



BULLETIN No. 6-SECOND SERIES. 



Studies of the American FALCONiDiE, by Robert Ridgway. 



Plate XXIV (after page 473). 



Polyborus cheriway, 5 figures. 

 Plate XXIII {ait&v page 473). 



Fig. 1. Ibycter americanus. 



Fig. 2. Ibycter (Daptrius) ater. 



Fig. 3. Milvago chimango. 

 Plate XXIV (after page 473). 



Fig. 1. Supramaxillary nasals and lachrymal of Phalcobienus (Senex) aiistralis. 



Fig. 2. Coracoid apparatus of Ibycter americanus. 



Fig. 3. Coracoid apparatus of Rostrhamus sociabilis (the buteonine form most 

 like Ibycter in external form). 



Fig. 4. Sternum of Milvago (chimachima?). 



Fig. 5. Sternum of Ibycter americanus. 



Fig. 6. Sternum of Polyborus tharus. 

 Plate XXV (after page 473). 



Fig. 1. Superior aspect of skull of Phalcob;euus (Senex) australis. 



Fig. 2. Pelvis of Milvago (chimachima ?). 



Fig. 3. Pelvis of Ibycter americanus. 



Fig. 4. Pelvis of Polyborus tharus. 

 Plate XXVI (after page 473). 



Fig. 1. Foot of Ibycter americanus. 



Fig. 2. Under surface of primaries of Milvago chimango. 



Fig. 3. Under surfaces of x>rimaries, &c., of Phalcobamus megalopterns. 



WOOD-CUTS IN TEXT. 



Skull of Mephites Froutata (Bulletin No. 1, second series, page 7). 



MAPS.— BULLETIN No. 3— SECOND SERIES. 



Preliminary map of the San Juan country, by A. D. Wilson (facing page 145). 



Map of Baker's Park and vicinity. 



Topography by A. D. Wilson ; geology by F. M. Endlich, page 164. 



