88 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



Genus MICROBATES Sclater and Salvin. 



Microbates<^ Sclater and Salvin, Nom. Av. Ncotr., 1873, 155. (Type, M. tor- 

 quatus Sclater and S&lvin— Rhamphoarnus collaris Pelzeln.) 



Very small, long-billed, long-legged Formic ariidie, similar in appear- 

 ance to Ramj^hocsenus but with shorter and broader bill, longer tarsi, 

 relatively longer toes (especially the hallux), narrower nostrils with 

 differently shaped operculum, and much shorter tail (only about half, 

 instead of four-fifths) as long as wing. 



Bill about as long as head, nearly straight, its width at latero- 

 frontal anti{3e much greater than its depth at same point and equal 

 to much more than one-third the distance from nostril to tip of 

 maxilla; culmen sharply ridged, straight for basal half (more or less), 

 then very gradually decurved until near end, where more strongly 

 decurved, the tip of maxilla minutely but distinctly uncinate; max- 

 illary tomium faintly concave, minutely notched subterminally; 

 mandibular tomium very faintly convex, at least terminally, without 

 trace of subterminal notch; gonys faintly convex basally, straight 

 terminally. Nostril exposed, distinctly separated from feathering of 

 latero-frontal antiae, narrow, longitudinal (slit-like), overhung by a 

 broad but not convex membraneous operculum. Rictal bristles 

 distinct but rather few and slender; feathers of chin without terminal 

 setse. Wing rather large, with longest primaries extending slightly 

 beyond secondaries, much rounded; fifth and sixth primaries longest, 

 the tenth (outermost) less than half as long as the longest, the ninth 

 very much shorter than, the eighth about equal to, secondaries. Tail 

 slightly more than half as long as wing, rounded (graduation equal to 

 much less than half the distance from nostril to tip of maxilla), the 

 rectrices (10) rounded at tip. Tarsus very long (decidedly longer 

 than whole culmen, nearly half as long as wing), slender, the acro- 

 tarsium faintly scutellate, the planta tarsi completely fused; middle 

 toe, with claw, decidedly shorter than tarsus (equal to or sliglitly 

 longer than exposed culmen) ; outer toe, wdth claw, reaching to about 

 middle of subterminal phalanx of middle toe, the inner toe decidedly 

 shorter; hallux much longer than inner toe (about as long as outer 

 toe), much stouter; basal phalanx of middle toe wholly united to both 

 lateral toes; claws moderate in size and curvature, that of the hallux 

 much shorter than its digit. Plumage full, soft, and blended, that 

 of rump and flanks elongated, more lax or fluffy; feathers of pileum 

 not elongated. 



Coloration. — Above plain brown; sides of head blackish and white, 

 or tawny; beneath white passing into dusky on flanks and under tail- 

 coverts, the chest crossed by a band of black (M. collaris) or under 

 parts of body gray, chest streaked with black and white, and throat 

 white bordered on each side by a black stripe; sexes ahke. 



"■"fiiKpdc, parvus et jiarrjc, qui incedit." (Sclater and Salvin.) 



