202 BULLETIN 195, UNITED STATES NATIONAL MUSEUM 



The measurements of 18 eggs in the Doe, Hanna, and Philipp col- 

 lections average 17.3 by 12.7 millimeters; the eggs showing the four 

 extremes measure 18.7 by 13.1, 16.4 by 12.6, and 16.5 by 12.2 millimeters. 



THRYOMANES BEWICKII CERROENSIS (Anthony) 



CEDROS ISLAND WREN 



HABITS 



The Cedros Island wren has a rather restricted range on the island by 

 that name and on the neighboring mainland of Baja California, in the 

 middle of the peninsula, between latitudes 25° and 30°. 



A. W. Anthony (1897) , who named and described it as a new species, 

 writes : 



The present species needs comparison with none of our western species of the 

 genus unless it be T. leucophrys, from which it is very easily separated by its much 

 shorter bill, as well as other discrepancies in size, as will be seen from the accom- 

 panying table of measurements. From specimens before me taken at Rosalia Bay, 

 55 miles east of Cerros Island, the new species is easily separated by much more 

 extensively gray lower parts, less heavily barred. The lower tail-coverts, and its 

 tail feathers have a terminal band of gray of not less than 4 millimeters, whereas 

 the main land bird has a semiobsolete bar of about 1 millimeter. The middle 

 rectrices are also less plainly barred in the mainland specimen, the bars becoming 

 somewhat obsolete near the shaft. 



Cerros Island Wrens were not common at any point on the island, though more 

 were seen about the pine timber on the higher ridges. 



Dr. Oberholser (1898) remarks: "The wide terminal band of gray 

 on the tail-feathers and lower tail-coverts, which Mr. Anthony regards 

 as a character separating the Cerros Island bird from charienturus, is 

 a purely individual variation, and consequently of no diagnostic value. 

 The same may be said of the indistinctness of the barring on the central 

 rectrices, which is observable to a greater or less extent in all the forms 

 of the genus." He says further, however: "The characters which 

 separate this form from leucophrys are the darker upper parts, rather 

 more deeply gray flanks, much shorter bill, appreciably shorter wing 

 and tarsus." 



Comparing it with its nearest neighbor on the mainland, Ridgway 

 (1904) says: "Similar to T. h. charienturus, but slightly smaller (the 

 bill decidedly so) and coloration slightly paler and grayer." 



I can find nothing to add about the habits of this subspecies. 



Four eggs in the P. B. Philipp collection measure 17.7 by 12.6, 17.1 

 by 12.7, 16.8 by 12.6, and 17.7 by 12.5 millimeters. 



THRYOMANES BEWICKII BREVICAUDA Ridgrway 



GUADALUPE WREN 



HABITS 



This well-marked form lived and died on Guadalupe Island, off the 

 coast of Baja California, where it is now evidently extinct. As this 



