CHERRIE: ORNITHOLOGY OF THE ORINOCO REGION. 273 
m. Larger, wing more than 75 mm.; top of 
head slate gray in sharp contrast with color 
of back 9 Sclatcrta schistacea cauren- 
m'. Smaller, wing less than 75 mm. and top of 
head uniform with back 9 Sclateria argenlata. 
"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." • (Myrmotker- 
ula. Myrmopagis. MUrorhopias, Herpsilochmus. Ramphocaerus, 
Cercomacra, Thamnomanes Myrtnoborus, Hypocnemis, Hapalocer- 
ctts, Myrmeciza, Myrmoderas. Formicarius). 
d. Bill long and slender, as long as head Ramphocaejius melanurus trin- 
itatis. 
d'. Bill not unusually long and slender. «o/ as long as head. 
e. Outstretched feet reaching little if any beyond the tips of the 
under tail coverts Thamtwmaties glaiicus. 
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 
I feathers tipped only with rufous) . 
inner webs of wing-riuills. 
g. Distance from tips of under tail-coverts to tip of tail not 
greater (usually less) than length of bill, and lower back 
not marked with rounded white or bufiy spots. 
h. 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) MyrmoboTus leucophrys leuco- 
pkrys. 
i'. No frontal band and superciliaries narrow (a con- 
cealed white dorsal spot) Myrtnoborus myotherina my- 
ft'. Sides of face not black. 
i. Tertials and secondaries with cinnamon buff tips .... Myrmotherula guttata. 
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 (f Myrmotherula cinereiven- 
k'. Light neutral gray below d* Myrmotherula cinereiventris 
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. 
/. A white shoulder patch. 
m. Tail-feathers narrowly tipped with white. . & Myrmotherula longipennis. 
m'. Tail not white tipped d* Myrmopagis schisticolor. 
I'. 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. 
jn. Both maxilla and mandible black (females 
as well as males striated with black on 
underparts) Myrmotherula cherriei. 
m'. Mandible pale, maxilla black, fc*males not 
strongly striated with black below Myrmotherula surinamensts 
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- 
r. Throat and breast yellow or pale yellow. 
j. Smaller, breast not (or less) distinctly squamate . . . Hypocnemis Jiavescens humilis. 
j'. Larger, breast more distinctly squamate Hypocnemis jiavescens Jlave- 
