:^66 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



opportunity to study them because of their retiring habits. All have 

 close, firm plumage, like tliat of a duck, and slender, rather elongated 

 bills, with perforate nostrils like those of rails. The feet are webbed, 

 and the tail is long and broad. While they fly readily when ap- 

 proached, more often they dive, as they are truly aquatic in habit. 



HELIORNIS FULICA (Boddaert): American Finfoot; Patico de Agua 



Figure 61 

 Colymbus fulica Boddaert, Table Planch. Enl., Dec. 1783, p. 54. (Cayenne.) 



Like a grebe, but with head and side of neck black ; streaked 

 prominently with white behind the eye, and on lower side of neck. 



Description. — Length 280 to 305 mm. Adult male, crown and 

 hindneck black, with a white line extending from above eye back 

 to upper neck ; back and wing coverts olive-brown ; wing feathers 

 fuscous ; rump and upper tail coverts brown ; tail black, tipped 

 narrowly with white ; throat and f oreneck white ; side of head below 

 eye white, in some washed lightly with buff; a black band at each 

 side of lower f oreneck, in some united across the front, separated 

 from the black of the hindneck by a broad white line ; a faintly 

 indicated buffy brown band across upper breast and adjacent sides ; 

 rest of breast and abdomen white ; sides and under tail coverts grayish 

 brown ; under wing coverts dark gray. 



Adult female, like the male, but with a prominent band of cinnamon 

 brown on the cheeks and adjacent sides of neck. 



Immature, like the adult, but with cheeks and sides of neck white. 



An adult female, taken on the Rio Chagres, at Juan Mina, January 

 18, 1955, had the iris dark brown; maxilla and side of mandible at 

 base dull red, becoming blackish at the extreme base, and on the tip 

 of the culmen; mandible light horn color on the sides, and light 

 neutral gray at the tip; bare edge of eyelids dull red, forming a 

 narrow ring ; lower tarsus, toes, and webs honey yellow ; three bands 

 on inner toe, four on the middle toe, five on the outer toe, and two 

 on hind toe dull black; upper third of tarsus dull brownish yellow; 

 a band of dull black on inner side, and on anterior face of tarsus, 

 and also on the posterior half of the outer face. 



Measurements. — Males (6 from Mexico, Costa Rica, Nicaragua, 

 and Panama), wing 138.4-152.0 (141.3), tail 83.0-91.0 (86.7), culmen 

 from base 30.0-33.6 (31.5), tarsus 22.4-24.0 (23.5) mm. 



Females (6 from Mexico, Costa Rica, Nicaragua, and Panama), 

 wing 133.3-142.2 (137.7), tail 78.0-81.5 (80.1), culmen from base 

 28.5-33.2 (30.3), tarsus 21.7-23.7 (22.7) mm. 



