434 BIRDS OF THE REPUBLIC OF PANAMA PART 3 



Description. — Length 175-185 mm. Adult (sexes alike), crown 

 rather dull black ; forehead, lores, and side of head slate-gray ; hind- 

 neck, back, and scapulars light gray, with a slight yellowish cast ; 

 upper back with slightly indicated dusky shaft lines ; rump white ; 

 upper tail coverts dark gray, edged with grayish white ; tail dusky, 

 tipped lightly with grayish white ; wings dusky black, coverts and 

 secondaries broadly edged with white ; foreneck and upper breast 

 pale grayish white ; rest of under surface, including axillars, under 



Figure 39. — -Sirystes, papanioscas copeton, Sirystcs sibilator albogriscus, male. 



wing coverts, and basal inner webs of primaries and secondaries, 

 white. 



Immature, gray and white, faintly bufify throughout. 



An adult female, taken at the Peluca Hydrographic Station on the 

 Rio Boqueron, had the iris dark brown ; tip of bill dull black; base of 

 maxilla fuscous, that of mandible dull brownish white; tarsus and 

 toes dark neutral gray ; claws black ; inside of mouth, including 

 tongue, orange. 



Measurements. — Males (10 from eastern Province of Panama and 

 Darien), wing 97.7-103.8 (101.4), tail 81.3-85.0 (83.2), culmen 

 from base 18'.9-21.3 (19.7), tarsus 18.1-19.7 (18.8) mm. 



Females (10 from Colon, eastern Province of Panama, and 



