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 Pitangiis sidplmrattts riifipcnnis, Myio- 

 setetes cayancnsis rtifipennis or M. tcxensis columbianns 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 alhigularis) 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 Venezuelan Cowbird (Molothriis bonariensis 

 venesuelensis) were found in the nest with those of the Spine-tails. 



SiPTORNis HYPOSTiCTA (Pelzeln). 



Synallaxis hyposticta Pelz., Sitz. Akad. Wien, 1859. p. 102. 

 Siptornis hyposticta Berlepsch & Hartert, p. 60. 



Noted only on the upper river at Munduapo and Nericagua. Speci- 

 mens were also taken at La Pricion on the Caura River 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. 



