30 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 95. 
in the humid section bordering the Gulf of Mexico. The region was 
marked by areas of scrub, open or dense, by pasturelands broken by 
thickets and groves, and by tracts of forest along the streams and in 
poorly drained areas. Below Liberia there were scattered marshes 
and shallow lagoons. Whether part of the pasturelands had origi- 
nally been in savanna it was difficult to say, but there were extensive 
savanna areas toward the mountains. 
It is hardly proper to attempt to list completely the characteristic 
birds of the arid Lower Tropical Zone from the small amount of field 
work on which this report is based. Instead I shall point out some 
of the interesting facts in distribution that have been evident. 
As characteristic birds of the arid division I may mention such 
forms as Scardafella inca, Eumomota superciliosa australis, Myiarchus 
nutting. nuttingi, Camptostoma imberbe, Polioptila plumbea bairdi, 
Icterus sclaterr sclaterit, and Aimophila rufescens hypaethrus. It was 
curious that near Liberia I found no species of the family Formi- 
cariidae; though I was certain that some form of Thamnophilus must 
occur, apparently it is found in very limited numbers. 
At the Hacienda Santa Maria on the lower slopes of the Cerro Santa 
Maria there was rather abrupt transition to the humid Lower Tropical 
Zone in the great forests that extended over the mountain and reached 
to the east over the broad, fairly level area at Los Cuadros. As 
remarked above, this was the watershed between the Atlantic and the 
Pacific drainages. Here I obtained Xiphorhynchus triangularis punc- 
tigulus, Sclerurus albigularis canigularis, Phaenostictus mcleannanr 
saturatus, Lophotriccus pileatus lutewentris, and Lamo leucothorax 
leucothoraz. 
In two instances I secured different forms of the same species at 
Liberia and on the Cerro Santa Maria. In the arid division I obtained 
Piraya cayana stirtont and Hylophilus decurtatus pallidus, while in the 
humid Lower Tropical area I found P. c. thermophila and H. d. decur- 
tatus. 
As one travels across the rather barren area of poor soil with low, 
scrubby oaks and scattered herbaceous vegetation toward the moun- 
tains the land rises, and there is a sudden transition at about 300 
meters elevation to a greener, more fertile region, beginning a short 
distance below the old, outlying ranch house at Las Delicias. The 
open slopes in November 1940 were covered with an abundance of 
ereen grass, and in the heavier woodland there appeared a dense 
undergrowth of a small bamboo. Above, the slopes were more open, 
covered with excellent pasturage, groves being found mainly in the 
hollows. The growth here was influenced by the rains, mists, and 
fogs that sweep across from the Atlantic side, and the area nearer the 
Hacienda Santa Maria must be considered a part of the humid section 
