70. HIEROFALCO. 411 



a". Head and entire underparts piu-e white, 



without any spots or streaks candicans ad., p. 411. 



b". Head, neck, and under surface of body 



white, with narrow brown streaks candicans ad., p. 411. 



b'. Tail white, with more or less remains of 

 distinct bars. 

 c". Upper surface of body white, distinctly 

 barred across with black ; breast pure 



white candicans ad., p. 411. 



d''. Upper surface light brown, the feathers 

 broadly margined with white, spotted 

 or barred near the base with the same 



colour candicans juv., p. 411. 



c'. Tail brown, barred on inner web with fulvous, 

 e ' '. Ijarger ; head white, streaked with brown ; 



wing in <S 13-2 inches, in $ 1(3-1 .... saker ad., p. 417. 

 /". Smaller ; head brown, the feathers with 

 rufous margins ; wing in c? 12'3 inches, 

 in 5 14-25 mexicanus ad,, p. 420. 



b. Thighs white, barred with black or grey. 



d'. Head and chest pure white holboelli ad., p. 415. 



e'. Head white, streaked with black. 



g". Larger ; chest white, streaked with black islandus ad., p. 414. 

 h". Smaller; chest pure white, not streaked holboelli ad., p. 415. 



/'. Head uniform bluish grey gyrfalco ad., p. 416. 



g'. Head brown, streaked with rufous; back 



banded with rufous; nape rufous saker ad. (=milvipes), 



c. Thighs gTey, margined and barred across with p. 417. 



■white . . ._ gyrfalco ad., p. 416. 



d. Thighs greyish or rufous brown, these colours 



prevailing and occupying the centre of the 

 feathers, which are more or less broadly mar- 

 gined, spotted, or notched with white. 

 A'. Tail ashy brown, with regular narrow ful- 

 vous bars across the feathers gyrfalco juv. p. 416, 



iskmdus juv, p. 414. 

 holboelli juv. p. 415. 

 «'. Tail nearly uniform ashy brown, with a few 



indications of spots near the tip holboelli ^u\., p. 415. 



k'. Tail rufous brown, broadly notched or barred 

 with fulvous on the inner web, and having 

 large rounded spots of the same colour on 

 the outer web saker juv., p. 417. 



1. Hierofalco candicans*. 



Le Gerfaut, Briss. Orn. i. p. 370, pi. xxx. fig. 2 (1760). 

 Gerfaut blanc des Pays du Nord, Buf. PL Enl. i. pi. 440 (1770;. 



* Gmelin appears to Lave derived his species from the " Gerfaut '' of Brisson. 

 The latter seems to have had a very good idea of the diflerenees of the Ger- 

 falcons, as also had Briinnich. Euflbn (and from him Gmelin) at first mixed 

 the three species hopelessly together, though he afterwards came to think that 

 there were three different races. In the ' Planches Enluminees ' I can find no 

 evidence that he was personally acquainted with the Greenland and Iceland 

 Falcons ; and I cannot help thinking that the fignrea in his large work were not 



