262 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



Color. Adult male (breeding plumage, P. U. O. C. 5596). 

 General color above, black mottled with bright chestnut ; the head white 

 striped with black. Below white, with a large area of 

 black on the chest and sides of the neck. FlG - ill- 



Head : Crown, forehead and occiput white ; the 

 crown streaked with black. The base of the forehead 

 black, extending into a narrow frontal line reaching to 

 the eyes on either side, and widening below and be- 

 hind into a crescent which runs into the black stripes 

 of the malar region, and by them is connected with the 

 black regions of the sides of the throat, the chest and | 



breast. Above this black a band of white which unites Arcnaria interpres in 

 with a broad white eyebrow and extends backward adult plumage about to 

 over the ear coverts. A white loral patch, separated breed. P. U. O. C. 

 from the white throat by a black line. S5 9 6 - One half natural 



size 



Neck: Hind neck white, with some black mott- 

 ling. Sides of neck and fore neck black ; throat white. 



Back: Mantle black, mixed with bright chestnut pr bright chestnut 

 and black feathers. Scapulars chiefly chestnut, the outer areas irregularly 

 marked and terminated with black. Accessory scapular plumes white. 

 The entire back below the mantle including the rump white. Upper 

 tail coverts chiefly black, the longer ones white. 



Tail : Rectrices black with white bases, and tipped with white, except 

 that in very old birds this white tip is not present on the central pair. 

 The black of the rectrices diminishing in area toward the outer feathers 

 forms a band, obvious when the tail is spread. 



Wing : Lesser upper coverts dusky, margined conspicuously with 

 white for the most part. Median upper coverts chiefly chestnut, some- 

 times mottled slightly with black. Greater coverts dusky, narrowly 

 edged and broadly terminated with white. Bastard wing and primary 

 coverts black, the inner coverts tipped with white. Primaries black with 

 white shafts, the inner ones with white bases and tips. Secondaries 

 chiefly white, becoming black toward the ends of the feathers, these black 

 areas decreasing toward the innermost secondaries leaving many of the 

 inner feathers of the group immaculate. The innermost secondaries 

 black, mottled with bright chestnut. 



Lower parts : Throat and under surface of the body from the center 



