428 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



allowing for forms subsequently described and additional genera which 

 it seems desirable to recognize, 200 species and subspecies and 30 

 genera may be considered a fair estimate. 



The Mniotiltidee contain a laj-ger proportion of monotypic genera 

 than most Oscine families, nearly one-half of the genera being rep- 

 resented by a single known species.' 



KEY TO THE GENERA OF MNIOTlLTIDiE. 



u.. Outermost (ninth) primary, but little, if any, shorter than secondaries (usually 

 much longer); eighth primary much longer than first (equal to or longer than 

 third); nostril longitudinal, with distinct superior membranous operculum. 

 b. Tarsus less than half as long as tail, very much less than twice as long as mid- 

 dle toe without claw. ( Mniotiltinx.) 

 c. Hallux longer than inner toe with claw, about equal to frontal length of tar- 

 sus. (Mnwtiltie.) Mniotilta (p. 431) 



cc. Hallux much shorter than inner toe with claw (about equal to inner toe 

 without claw), much shorter than frontal length of tarsus. 

 d. Eictal bristles inconspicuous, sometimes obsolete; if distinct, much less 

 than half as long as exposed culmen, and bill not depressed, its, basal 

 depth equal to or greater than its basal width. 

 e. Tail not longer than wing (usually much shorter) ; bill slender, its basal 

 depth not more than half the distance from nostril to tip of maxilla. 

 /. Bill narrowly cuneate, with tip very acute and not distinctly, if at all, 

 decurved, and without distinct, if any, tomial notch. {Helinaiie.) 

 g. Kictal bristles obsolete. 

 /(. Larger (wing more than 63.5). 

 i. Inner webs of rectrices without white ; wings and tail plain olive or 

 brown; nopronounced yellow; no subterminal notch to maxillary 

 tomium; basal phalanx of middle toe united to outer toe for 

 much less than its entire length, to inner toe for not more than 

 half its length. 

 j. Bill much compressed, with culmen straighWind conspicuously 

 ridged and elevated between nostrils; pileum plain brown. 



Helinaia (p. 436) 



jj. Bill moderately compressed, with culmen not conspicuously 



ridged nor elevated between nostrils; pileum 5-striped (3 buff 



and 2 black stripes) Helmitheros (p. 438) 



a. Inner webs of rectrices largely white; wings and tail bluish gray; 

 under parts (whole head in adult male) yellow; maxillary 

 tomium with slight subterminal notch ; basal phalanx of middle 

 toe united for nearly entire length to outer toe, for more than 



half its length to inner toe Protonotaria (p. 442) 



hh. Smaller (wing less than 63.5 — usually much less), 

 i Tail relatively shorter (difference between length of tail and 

 length of wing nearly, if not quite, equal to one-fourth the length 

 of the latter); throat not orange nor back black; if back olive- 

 green, no white superciliary stripe nor chestnut spot on breast. 



Helminthophila (p. 445) 



' The monotypic genera belonging to North and Middle America are the following: 

 Mniotilla, Helinalci, Helmitheros, Protonotaria, Peucedramus, Catharopeza, Leucopeza, 

 Microligea, Icteria, Cardellina, and Evihlypis. 



