BIRDR OF NORTH AND MTDDLK AMP:RI0A. 665 



Clatherpes'] Kiimichrasti Ridgway, Man. N. Am. Birds, 1887, 549. 

 Hiilorchilus sumicJirdsti Nelson, Auk, xiv, Jan., 1897, 72 (Motzorougo, Vera 

 Cruz, 800 to 1,200 ft.; measurements; liabits). 



Genus MICROCERCU LUS Sclater. 



Mlcrocerculus Sclater, Cat. Am. Birds, 1862, 19. (Type, Turdtix Jxnnhla Bod- 

 daert. ) (See Baird, Review Am. Birds, 1864, 113; diagnosis). 



Small Troglodytidie (wing 50-60 mm.) most resembling- Jf, nlco- 

 rhind^ but with tail much less than half as long as wing, bill much 

 longer (exposed culmen nearly one-third as long as wing). Avitli tip of 

 maxilla more strongly and abruptly decurved, lateral toes reaching 

 only to subterminal joint of middle toe, and sides of neck plain brown 

 or gray. 



Bill al)out as long as head, straight, with tip of maxilla almost 

 abruptly decurved, depressed at base, its depth at latero-frontal antiae 

 equal to nearly or quite one-third the distance from nostril to tip of 

 maxilla, but less than its width at same point; exposed culmen equal to 

 or longer than middle toe without claw but shorter than tarsus, straight, 

 or nearl}- so, to near tip, where rather abruptly decurved; gonys 

 much shorter than distance from nostril to tip of maxilla, straight or 

 almost imperceptibly convex, its base rather prominent from narrow- 

 ness of mandibular rami; maxillary tomium nearly straight, distinctly 

 notched subterminalh", the rictus decidedly and rather abruptly detlexed. 

 Nostral mostly closed by the broad, convex overhanging (decumbent) 

 membraneous operculum, but open posteriorlv (against feathering of 

 latero-frontal antia^, from contraction of the operculum at its posterior 

 end.** Rictal bristles obsolete. Wing short, very concave beneath, 

 much rounded; seventh, sixth, and fifth primaries longest; eighth 

 about equal to third; ninth shorter than secondaries, less than twice 

 as long as tenth. Tail excessively short, less than three-eighths to a 

 little more than two-fifths as long as wing, not much longer (some- 

 times shorter) than tarsus, much roimded or graduated, the rectrices 

 rounded or subacuminate at tip. Tarsus long and slender, decidedl}' 

 (sometimes much) longer than exposed culmen, nearly two-fifths as 

 long as wing, the acrotarsum distinctly scutellate, the planta tarsi 

 booted; middle toe (with claw) shorter than tarsus; outer toe (without 

 claw) reaching to or slightly beyond subterminal joint of middle toe, 

 its claw falling far short of base of middh^ claw; inner toe equal to or 



"The form of the nostril in this genus is thus accurately described by Salvin 

 (Proc. Zool. Soc. Lond., 1866, 70, 71): The nostril is partially covered by a mem- 

 brane, which, being convex along its unattached lower edge, meets the lower margin 

 of the nasal cavity toward its anterior end, leaving the posterior end open and 

 comma-shaped, the tail of the comma extending anteriorly. No .«!eptum or division 

 is seen externally, but by raising the valvular membrane it appears. This septum, 

 however, is perfectly free and unattached to the meml)rane of the nostril [operculum] 

 and does not adhere to it as Prof. Haird states (with dmiiit'). The perfect nostril 

 never appears double. (See Baird, Review \\\\. Birds, 1864, li:>, 114.) 



