Dr. E. A. Goeldi on Myiopatis semifusca. 109 



Tick. In describing the type M. Oustalet compares it with 

 A. torqueola, but it evidently belongs to quite a different 

 section of the genus, having the feathers of the sides and flanks 

 ornamented with a large subterminal white spot and terminal 

 black band, as in A. brunneipectus. From the latter species it 

 appears to differ only in having the forehead chestnut instead 

 of whitish buff and in lacking the pale buff superciliary 

 stripes. In the description the wings are said to resemble 

 those of A. torqueola, but the figure (op. cit.) represents the 

 wing- coverts as being pale blue tipped with chestnut and 

 with a subterminal black spot. If the figure correctly repre- 

 sents the colouring of this bird's wing, it is unlike that of 

 any other member of the genus. 

 Hab. Tonkin and Anam. 



XVII. — On Myiopatis semifusca, a small Neotropical Tyrant- 

 bird, harmful to Tree- culture as a Disseminator of the parasitic 

 Loranthacece. By Prof. Dr. Emil A. Goeldi, H.M.B.O.U., 

 C.M.Z.S., Director of the Para Museum. 



Our acquaintance with the Neotropical Avifauna does not 

 up to the present go far beyond catalogues and descrip- 

 tions of bird-skins, and, as to its most important features, 

 still remains unquestionably in the " cabinet phase." It is 

 well to remember that the systematic naming and diagnosis 

 of a species is merely the threshold at the entrance to the 

 essential knowledge of its life-sphere — a small fraction only 

 of the sum total of the natural history of the species. The 

 truth of this assertion especially impresses him who calls to 

 mind the family of the Tyrants, which plays so prominent a 

 rdle in the physiognomy of the South-American Avifauna — 

 a family to the complexity and richness of which I have 

 already more than once alluded in previous publications. 

 These facts have been, moreover, frequently pointed out by 

 nearly all special investigators of South-American orni- 

 thology. What light has been thrown upon the life-history 

 of this host of Tyrants (large, middle-sized, and small — 



