56 BfRDS OF BRITISH GUIANA. 



culmen is about four-fifths the length of the tarsus. The wing is 



rounded, the fourth, fifth, sixth, and seventh primaries longest 



and subequal, the third shorter than the eighth and ninth but 



much longer than the tenth. The tail also rounded at the tip and 



graduated, the two middle feathers longest and about five-sevenths 



the length of the wing. Coloration : male and female quite 



different. 



Key to the Species. , 



A. Under surface streaked. 



a. Throat and breast slate-grey streaked 



with white' S. ncBvia 6 , ^- 5Q. 



h. Throat and breast white streaked with 



fawn-brown 8. ncBvia ^, ip. 57. 



B. Under surface uniform, not streaked. 



e. Larger, under parts ash-grey S. leutiostigma 6 , p. 57. 



c'. Larger, and paler chestnut oil the 



under sm-face 8. leuoostigma ^ , ^. 58. 



d. Smaller, under surface blackish slate- 

 colour 8. saturata S , T^. 58. 



<?'.' Smaller, and darker chestnut on the 



under surface S.satwrata ^ ,^. 59. 



383. Sclateria nsevia. 



Surinam Ant-crbeper. 



Sitta navia Gmel. Syst. Nat. i. p. 442, 1788 (Surinam). 

 Ileterocnemis lineata Cab. in Schomb. Eeis. Gruian. iii. p. 685, 1848. 

 Seterocnemis navia Salvin, Ibis, 1885, p, 427 (Camacusa) ; Sclater, 



Cat. B. Brit. Mus. xv. p. 275, 1890 (Camacusa). 

 Sclateria ncevia Brabourne & Chubb, B. S. Amer. i. p. 208, no. 2906, 



1912. 



Adult male. General colour above dark slate-colour, somewhat 

 darker and inclining to black on the upper wing-coverts, all of 

 which are tipped with white, including the hastard-wing and 

 primary-coverts ; primary and secondary quills dark brown ; tail 

 sooty-black ; head like the back, the short feathers surrounding 

 the eye and sides of the face have white shaft-lines; throat 

 white, the feathers slightly tipped with slate-grey ; remainder of 

 the under surface sla,te-colour, but paler than the back, with 

 longitudinal white centres to the feathers on the fore-neck, 

 breast, and abdomen, somewhat darker and almost entirely 

 uniform on the flanks, under tail-coverts, and under wing-coverts ; 

 nnder surface of quills and lower aspect of tail dark brown. 



Total length 145 mm., exposed culmen 21, wing 71, tail 51, 

 tarsus 25. 



