400 Six New Species of Birds of the Families 



that the air contained in the air-bladder, when completely 

 detached from the oesophagus, does not escape on pressure. 



By an examination of some fresh, almost full grown speci- 

 mens, the air-bladders of which were well filled with air, I have 

 been enabled to establish this fact. I have to observe, that 

 the air-bladder cannot be isolated from the oesophagus, for the 

 purpose I had in view, until a portion of the abdominal walls 

 and of the gills has been removed.* 



It is therefore certain, that the Aphredoderus is a Hetero- 

 pygius among the Acanthopterygii, the only representative of 

 a family analogous to that of which the Amblyopsis is the only 

 representative among the Malacopterygii abdominales. 



For the specimens examined by me I am indebted to F. W. 

 Putnam, Esq., Superintendent Essex Institute, Salem, Mass. ; 

 Dr. Abbott of Trenton, and Dr. John L. Le Conte of Phila- 

 delphia. 



XL. — Descriptions of Six New Species of Birds of the Fami- 

 lies HlRUNDINIDJE, FoRMICARIDJS, TyRANNID^E, and TrOCHI- 

 LIDjE. 



By Geo. N. Lawrence. 



Read December 10th, 1866. 



Fam. HlRUNDINIDJE. 



l. nirimdo sequitorialis, nov. sp. 



Above shining light green, darker on the crown, where it is 

 somewhat of a bluish shade ; rump white, with the shafts of the 

 feathers dusky black ; upper tail coverts of a dusky green, with 

 their tips shining green, like the back ; the two central tail feathers 

 and the outer webs of the others are of a dull dusky green, the 



* In examining the air-bladder I ascertained that it has a layer of striped 

 muscles. 



