44 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



Science, University of Miami, in 1961, during a cruise as naturalist 

 on the yacht Argosy, A. Glassell owner, found these petrels common 

 from September 6 to 14 in the Bay and Gulf of Panama, even among 

 the boats anchored off Panama City. Apparently this was the 

 period of their movement from their southern nesting grounds. As 

 noted below one specimen taken was the typical subspecies. Another 

 that came aboard ship in Colombian waters was the race kelsalli, 

 so that it appears that both races were in company. 



OCEANODROMA TETHYS TETHYS (Bonaparte) 



Thalassidroma Tethys Bonaparte, Tagebl. der 29. Versaml. Deutsch. Naturf. 

 Aerzte, Wiesbaden, Beilage, Sept. 25, 1852, p. 89. (Galapagos Islands.) 



Characters. — Larger, its greater size indicated by longer wing; 

 Males (3 specimens, from the Galapagos Islands), wing 129.0-132.6 

 mm.; females (3 specimens from the Galapagos Islands), 132.9-136.0 

 mm. 



Visitor to Pacific waters off Panama. 



This, the nominate race of the species, breeds on the Galapagos 

 Islands, and after the nesting season ranges in the eastern Pacific 

 north to the latitude of southern Baja California, and south to that 

 of southern Ecuador. 



A skin in the British Museum (Natural History) collected by the 

 St. George Expedition, with a wing measurement of 129.7 mm., was 

 taken on September 9, 1924, "20 miles south of Panama." Another 

 in the University of Miami Museum, with the wing 129.4, prepared 

 by D. R. Paulson, came to lights on the yacht Argosy when near 

 lat. 07° 10' N., long. 79° 04' W., a point due south of the western- 

 most islands in the Perlas group and about midway on a line from 

 the southernmost point on the Azuero Peninsula to the international 

 boundary between Panama and Colombia. Though well offshore at 

 the southern end of the Gulf of Panama, this is within waters that 

 may be regarded as to be included for pelagic species. 



OCEANODROMA TETHYS KELSALLI (Lowe) 



Thalassidroma tethys kelsalli P. R. Lowe, Bull. Brit. Orn. Club, vol. 46, Nov. 4, 

 1925, p. 6. (Isia Pescadores, oflf Ancon, Peru.) 



Characters. — Similar to O. t. tethys, but smaller, with shorter 

 wing: Males (4 specimens at sea off Peru, Colombia, and Panama), 

 wing 122.7-125.9 rnm. ; females (3 specimens at sea off Colombia and 

 Panama), 123.4-128.0 mm. 



Visitor to the Pacific waters of Panama. 



