480 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



Genus CISTOTHORUS Cabanis. 



Cistothorasa Cabanis, Mus. Hein., i, 1850, 77. (Type, Troglodytes stellaris Lich- 

 tenstein. ) 



Very small Troglodytidee (wing less than 50 mm.) resembling 

 Tehnatodytes, but with exposed culmen much shorter than middle toe 

 (without claw), the bill stouter and less decurved (its depth at frontal 

 antise equal to nearly half the distance from nostril to tip of maxilla, 

 or sometimes much more than half), tail graduated for more than one- 

 third its length, and with the pileum, as well as back, streaked.* 



Bill much shorter than head, rather stout, its depth at latero-f rontal 

 antiee decidedly more than one-third the distance from nostril to tip 

 of maxilla and about equal to its depth at same point; exposed cul- 

 men decidedly shorter than middle toe without claw, nearly straight 

 for most of its length, or gradually, though slightly, curved from base; 

 gonys decidedly shorter than distance from nostril to tip of maxilla, 

 straight; maxillary tomium slightly concave, without trace of subter- 

 minal notch. Nostril longitudinal, ovate or guttate (pointed anter- 

 iorly), overhung by a distinct operculum, its posterior end in contact 

 with feathering of nasal fossa. Rictal bristles absent. Wing short, 

 rounded; eighth, seventh, and sixth primaries longest, or seventh, sixth, 

 and fifth longest, the eighth scarcely shorter, or eighth to fifth longest 

 and equal; ninth shorter than third, sometimes shorter than first, about 

 twice as long as tenth, or a little less. Tail nearly as long as wing 

 (seven-eighths to seventeen-eighteenths as long), graduated for one- 

 third its length or more (for two-fifths its length in C. stellaris and C. 

 elegans), the rectrices rather narrow and slightly tapering terminally, 

 but with tip broadly rounded. Tarsus longer than middle toe with 

 claw, two-fifths as long as wing, or more, the acrotarsium distinctly 

 scutellate, the planta tarsi booted; outer toe (without claw) reaching to, 

 but not beyond, subterminal joint of middle toe, its claw falling much 

 short of base of middle claw ; inner toe (without claw) reaching to slightly 

 beyond subterminal joint of middle toe; hallux (without claw) slightly 

 longer than inner toe (without claw), but much thicker, its claw shorter 

 than the digit (sometimes nearly as long); basal phalanx of middle toe 

 coherent to outer toe for about two-thirds its length, to inner toe for 

 slightly less; base of inner toe united exteriorly to base of hallux. 



Coloration. — Above brown, the back conspicuously streaked with 

 black and white, the pileum also streaked,' at least with black; wings 

 and tail variegated with black, mostly in form of bars; under parts 

 buffy or pale tawny, paler (usually whitish) on throat and abdomen. 



Nldification (of <7. stellaris). — Nest globular, with entrance a small 

 hole in one side, composed of grass or sedge blades, attached to upright 

 aquatic grasses or sedges; eggs immaculate white. 



a From " Cistsohliipf er. " 



!< Except in young and in adults of one or two South American species. 



