38 



BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



to ochraceous-buff; rest of under parts plain deep buff to nearly 

 ochraceous-buff (or between ochraceous-buff and clay color); length 

 (skins), 134-155 (147); wing, 67-71 (68.6); tail, 54-59 (56.3) ; culmen, 

 17-20 (18.7); tarsus, 25-27 (26.1); middle toe, 15-16.5 (15.8). « 



a Eight specimens from Panama (mainland). 



The series examined from Panamd comprises three adult males in dark, heavily 

 barred plumage, like the type, and ten which are more or less decidedly lighter in 

 color, some of them indistinguishable, so far as I am able to see, from Colombian 

 examples labeled Thamnophilus albicans. In fact, unless there are two forms of the 

 species in Panamd, which is hardly probable, the individual variation in this species 

 is much greater than in T. doliatus, which is reasonably constant within definite 

 geographic areas. At present I have neither the material nor time necessary for 

 more satisfactorily working out the problem, which, judging from the material 

 examined, is a very complicated one. 



The following measurements of specimens belonging to the radiatus group are given 

 below for comparison with those of Panamd examples: 



