CHERRIE : ORNITHOLOGY OP THE ORINOCO REGION. 273 



m. Larger, wing more than 75 mm.; top of 

 head slate gray in sharp contrast with color 



of back 9 Sclaieria schislacea cauren- 



sis. 

 7n'. Smaller, wing less than 75 mm. and top of 



head uniform with back 9 Sclaieria argenlala. 



"Nostrils more or less narrow and longitudinal, more or less dis- 

 tinctly operculate, or if broadly oval or roundish the remainder of 

 nasal fossae occupied by membranous integument." ' (Myrmolher- 

 iila, Myrmopagis, Microrhopias, Herpsilochmus, Ramphocaerus, 

 Cercomacra, Thamnomanes Myrmoborus, Hypocnemis, Hapalocer- 

 cus, Myrmeciza, ilyrmoderas, Formicarius). 



d. Bill long and slender, as long as head Ramphocaenus melanurus Irin- 



ilalis. 

 d'. Bill not unusually long and slender, not as long as head. 



e. Outstretched feet reaching little if any beyond the tips of the 



under tail coverts Thamnomanes glaucus. 



e'. Outstretched feet reaching much beyond the end of the under 

 tail coverts. 

 /. A restricted, sharply defined, buff colored area at the base 

 of the inner webs of the wing-quills. 

 g. Entire top of head, forehead, crown and occiput rufous 



(the crown feathers tipped only with rufous) Formicarius ruficeps. 



g'. Wide frontal band black, crown and occiput rufous Formicarius colma colma. 



/'. No restricted, sharply defined buff colored area at base of 

 inner webs of wing-nuills. 

 g. Distance from tips of under tail-coverts to tip of tail not 

 greater (usually less) than length of bill, and lower back 

 nol marked with rounded white or buffy spots. 

 b. Sides of face, lores and auriculars black. 



i. With broad frontal and superciliary stripe, white in 

 males, rufous in females (no concealed white dorsal 



spot) Myrmoborus leucophrys leuco- 



phrys. 

 i'. No frontal band and superciliaries narrow (a con- 

 cealed white dorsal spot) Myrmoborus myolherina my- 



olherina. 

 h' . Sides of face not black. 



i. Tertials and secondaries with cinnamon buff tips .... Myrmotherula gullata. 

 i'. No cinnamon buff tips to tertials or inner secondaries. 

 j. General color of under parts gray and throat prac- 

 tically uniform with breast. 



k. Slate gray below (^Myrmotherula cinereiven- 



tris cinereivenlris. 



k'. Light neutral gray below d'Myrmotherula cinereivenlris 



pallida, 

 j'. General color of under parts (gray) in sharp con- 

 trast with black or white throat; or with head and 

 back conspicuously striated. 

 k. Breast gray. 



I. A white shoulder patch. 



m. Tail-feathers narrowly tipped with white. . d' Myrmotherula longipennis. 



m' . Tail not white tipped cfMyrmopagis schislicolor . 



v. No white shoulder patch Myrmoborus melanopogon. 



k'. Breast not gray; and head and back striated. 

 /. General color of under parts yellow (pale or 

 lemon) ; and bill much more than one-half as 



long as tail Myrmotherula pygmaea. 



I'. General color of under parts white or buffy, 



and bill little if any more than one-half the 



length of the tail. 



m. Both maxilla and mandible black (females 



as well as males striated with black on 



underparts) Myrmotherula cherriei. 



rn'. Mandible pale, maxilla black, females not 



strongly striated with black below Myrmotherula surinamensis 



surinamensis. 

 g'. Distance from tips of under tail-coverts to tip of tail 

 greater than length of bill; or lower back marked with 

 rounded white or buffy spots. 

 h. Back more or less striated. 



i. Gray or grayish white below Herpsilochmus sticturus stic- 



turus. 

 i'. Throat and breast yellow or pale yellow. 

 j. Smaller, breast not (or less) distinctly squamate . . . Hypocnemis flavescens humilis. 

 j'. Larger, breast more distinctly squamate Hypocnemis flavescens flave- 

 scens. 



'Ridgway 1. c. p. 12. 



