NATURAL SCIENCES OF PHILADELPHIA. 475 



Falco trifasciatus, Natterer. (fide Pelzeln.) 



Olimacocercus concentricus, juv. Cabanis, in Tschudi Fauna Peruana, 99. 



Micrastur guerilla, Cass. 



CUmacocercus zonotlwrax, Cabanis. 



Micrastur leucauchen, Scl. and Salv., P. Z. 8., 1869, 3G7. 



4. Micrastur iiEucAucHEN. (P. 80.) 

 Falco leucauchen, Temni. 



5. Micrastur concentricus. (P. 81.) 



Falco concentricus, Illig. Nisus concentricus, Lesson. CUmacocercus con- 

 centricus, Caban. in Tscbudi Fauna Peruana, 18 and 98. Micrastur 

 concentricus, Pelz. Orn., Nov. 1865, 9. 



Falco senex, Natterer in Mus. Vindob. (fide Pelzeln.) 



Micrastur gilvicollis, Scl. & Salv., P. Z. S., 1869, 368. 



Sharpe, B. BowDLERCatalogue of the Accipitres, or the Diur- 

 nal Birds of Prey in the collection of the British Museum. Lon- 

 don, June, 1874, 8vo. pp. i.-xiii., 1-479, pis. xiv. Genus "17 

 Micrastur," pp. 74-80. The following- Key to the Species" is 

 given. 



a. Larger: underneath entirely uniform, not barred. 



a'. With a white or creamy buff collar round hind neck. 



semitorquatus, p. 75. 

 V. With no collar. mirandollei, p. 76. 



b. Smaller: underneath barred in a most regular manner. 



c'. Flanks white, barred with grayish-black. 

 c". Above uniform slate color, brown, or blackish-gray. 

 c">. Foreneck more or less tinged with orange-rufous. 



ruficollis, % , p. 76. 

 d"'. Foreneck barred with white and black. 

 c"". Lower abdomen and vent white. gilvicollis, % , p. 78. 

 &. Lower abdomen and vent distinctly barred like the' rest of 

 under surface. guerilla, % , p. 79. 



d". Back rufous or rufous-brown ; head ashy-gray or grayish-black, 

 in evident contrast. 

 e'. Chest orange-rufous. ruficollis, 9 , p. 76. 



f". Chest white, barred with grayish-black. 



e". Head and sides of neck ash-gray. guerilla, Q, p. 79. 



/"". Head and sides of neck grayish-black, the latter s'lightly 

 washed with rufous. zonotlwrax, 9 , p. 79 



d'. Flanks uniform bright chestnut. castanilius,^ p. 80. 



> According to Mr. Salvin (in Epist., May 6, 1875), this bird "turns out 

 to be an African species belonging to the genus Accipiter seu Nisus. The 

 South American locality given by Verreaux is quite wrong. It is almost 

 identical with Astur tibialis, differing only in size." 



