56 



BIRDS OF THE REPUBLIC OF PANAMA PART 4 



Steadman examined skeletons of Donacobius and found a number of 

 wrenlike characters, although in some other respects the osteology ap- 

 peared to be intermediate between wrens and mimids. Mary H. Clench 

 (pers. comm.) has found that Donacobius has the distinctive and 

 unique pteryolosis of the Troglodytidae. It appears that on the basis of 

 its specialized characters, Donacobius is clearly referable to the Troglo- 

 dytidae, and it remains to be determined whether its other characters 

 are merely primitive within the 10-primaried oscines or are indeed indic- 

 ative of a derivation of the Troglodytidae from the Mimidae. S. L. O.] 



KEY TO SPECIES OF TROGLODYTIDAE 



1. Throat solid black 2 



Throat brown, white, buffy or streaked 3 



2. Black extending to breast. 



Black-throated Wren, Thryothorus atrogularis. p. 94 

 Black limited to throat ; breast chestnut. 



Sooty-headed Wren, Thryothorus spadix. p. 95 



3. Throat white or buffy 4 



Throat brown or black and white 15 



4. Head and underparts pure white. 



White-headed Wren, Campy] orhynchus albobrunneus brachypterus. p. 60 

 Crown dark 5 



5. Crown black 6 



Crown brown 7 



6. Total length more than 200 mm. 



Black-capped Donacobius, Donacobius atricapillus. p. 57 

 Total length less than 160 mm 7 



7. Crown entirely black or washed with brown, total length 92-105 mm, tail very 

 short. 



White-breasted Wood- Wren, Henicorhina leucosticta. p. 110 

 Crown entirely black, total length 126-156 mm; tail longer, of normal pro- 

 portions. Bay Wren, Thryothorus nigricapillus. p. 85 



8. Back streaked black and white. 



Sedge Wren, Cistothorus platensis lucidus. p. 66 

 Back unstreaked 8 



9. Undersurface partly or entirely barred black and white. 9 



Undersurface not barred 10 



10. Undersurface with band of solid black, abdomen barred black and white. 



Black-bellied Wren, Thryothorus fasciatoventris. p. 96 

 Side of head and undersurface entirely barred black and white. 



Riverside Wren, Thryothorus semibadius. p. 92 



11. Breast definitely gray; tail very short. 



Whistler Wren, Microcer cuius marginatus luscinia. p. 121 

 Breast whitish or washed with light brown 12 



12. Superciliary prominent, white 13 



