CHERRIE: ORNITHOLOGY OF THE ORINOCO REGION. 261 
sapling, and that at that time was some 2.13 m. above the sur- 
face of the water. (The sapling stood in a flooded area and at that 
level of the water was perhaps one hundred meters from the river 
shore.) Masses, similar to that at which the Spine-tails were work- 
ing, are common all along the river and represent in many cases 
veritable accumulations of drift but quite as often they are doubtless 
the old nests of such species as Pitangus sulphuratus rufipennis, Myio- 
zetetes cayanensis rufipennis or M. texensis columbiamis that have been 
submerged during the flood season, and impregnated with the fine sedi- 
ment from the surrounding water. After the waters recede, the mud filled 
masses of drift become tenanted with many forms of insect life and soon 
develop into a favorite hunting ground for various species of insect 
feeding birds that gradually tear them to pieces, often piercing them 
with tunnels in their search for insect prey. It was such a torn and 
ragged bit of drift that the Spine-tails laid claim to it as their own spe- 
cial property. The interior was hollowed out and enlarged, and 
finally one of the entrances that had formed a part of a tunnel through 
the nest was closed, some dry soft leaves and wood-fiber were taken in 
as a foundation for an inner nest lining of grey lichens — the nest was 
completed but outwardly still looked a mere bunch of drift. 
While the form of this nest, the materials employed in its general 
structure and the site chosen all differ widely from the nests of other 
species of spine-tails that I had opportunity to examine (such as that 
described under Synallaxis albescens albigularis) there remains, in the 
use of grey lichens as the inner lining of the nest, a characteristic com- 
mon to all. Is this use of grey lichens in lining the nest cavity an 
hereditary custom descended from a distant common ancestor? 
Two eggs of the \'ene/!uelan Cowbird (Molotlinis bonaricnsis 
vencziiclcnsis) were found in the nest with those of the Spine-tails. 
SiPTORNis iiYPOSTiCTA (Pelzeln). 
Synallaxis hyposticta Pelz., Sitz. Akad. Wien, 1859. p. 102. 
Siptoniis hyposticta Berlepsch & Hartert. p. 60. 
Noted only on the upper river at Munduapo and Nericagua. Speci- 
mens were also taken at La IVicion on the Caura Ri\er by Klages. 
In the American Museum collection there is a single specimen from 
La Union on the Caura River, an adult male, collected October 23rd. 
