Kc>i to the Genera. 



a. Bill narrow ; breadth at forehead not more 



than half length of culmen ; rictal bristles 

 well developed. 

 '. Sexes different in coloration. 



a". Axillaries and under wing-coverts in 

 both sexes uniformly of one colour or 

 very nearly so ; lower plumage never 

 blue nor chestnut combined with black 



or blue MKBULA, p. 121. 



//'. Axillaries and under wing-coverts in 

 both sexes of two colours in strong 

 contrast ; arrangement of colours in 

 axillavies transposed in under wing- 

 coverts GEOCICHLA, p. 130 



c". Axillaries and under wing-coverts in 

 males of one colour, in females more 

 or less barred with two colours ; lower 

 plumage of males wholly blue, or chest- 

 nut combined with blue or black, in 

 females squamated. 

 a'". Tail very much longer than half 



wing PETBOPHILA, p. 142. 



It" . Tail about equal to half wing MONTICOLA, p. 147. 



I'. Sexes alike in coloration. 



d' 1 . Axillaries and under wing-coverts en- 

 tirely of one colour TURDUS, p. 148. 



e. Axillaries and tinder wing-coverts of 

 two colours ; arrangement of colours 

 in axillaries transposed in under wing- 

 coverts. 



c'". Lower plumage distinctly barred or 

 spotted ; rictal bristles few and 



lateral OREOCINCLA, p. 151. 



d'". Lower plumage squamated; rictal 

 bristles numerous, and anterior ones 

 projecting forwards over nostrils .... ZOOTHERA, p. 156. 



b. Bill broad ; breadth at forehead more than half 



length of culmen ; rictal bristles obsolete . . COCHOA, p. ]58. 



Genus MERULA, Leach, 1816. 



I restrict this genus to those Thrushes in which the sexes are 

 different in coloration and in which the under wing-coverts and 

 axillaries in both sexes are uniformly of one colour or nearly so. 

 The lower plumage of the Thrushes of this genus is, moreover, 

 never blue, nor chestnut combined with black or blue. 



In Met-ula the bill is about half the length of the head ; the 

 rictal bristles moderate ; the wing long and sharp, the first primary 

 being small ; the tail rather ample, and the tarsus long. The under- 

 side of the wing has no pattern. 



