BIKDS — TVKANNINAE — C0NT0PU8. 



187 



Comparative measuremenls of species. 



GENERAL REMARKS. 



There is, perhaps, no group in ornithology, certainly none among American birds, the species 

 and genera of which are so difficult to determine as tliose of the small olivaceous flycatchers. 

 The variations of size, color, and proportions are generally very slight, (though constant,) and 

 only to be appreciated after a close examination and actual comparison of specimens, as well as 

 long familiarity with the subject. Very few of the older authors describe the species so that they 

 can be recognized at all, and the identification is usually made from statement of locality, habit, 

 or common name. Wilson was the first to give accurate and intelligible descriptions of the 

 species inhabiting the United States, and it would have avoided much confusion if they had 

 been actually the first presented to the world. , 



In comparing the small North American olivaceous flycatchers together, usually known as 

 species of Tyrannula, I find two well marked groups worthy of generic separation : one with 

 short legs and pointed wings, the other with longer legs and rounded wings. In this, however, 

 it becomes a question what is to be done with the old name. The type of Tyrannula, Swainson, 

 (1827,) is the Mtiscicapa harhata of Gmelin, a species with a yellow spot in the middle of the 

 crown, and the rump yellow, the bill very broad and with the bristles equalling it in length.' 

 All these characters, and others, are entirely difl:erent from those attaching to our species, and 

 the same generic name cannot be used for them without great impropriety. 



The same objections apply to Myiobius of Gray, (1838,) this being a simple substitute for the 

 Tyrannula, supposed to be nullified from its resemblance in sound to Tyrannulus of prior date. 

 The two names, however, are sufficiently distinct to involve no difficulty in their use. 



Reichenbach makes numerous species among the Tyranninae, (Avium Systema Natura3, plates 

 65, 66, 67,) but, as far as I can judge from his figures, none are applicable here. In the 



' Ttbajj.scla barbata, Swaiii.sou. 



Mitscuapa barbata, Gm. I, 1788, 933.— Latham, Ind. Orn. II, 1790, 488. 

 Muscipeta barbata, Pr. Max. Beitrage, IH, 934. 

 Tyrannula harbala, Swainson, Zool. Jour. Ill, Doc. 1827, 359. 

 Myiobius barbalus, Bprmeister, Thiere Bras. II, I85G, 501. 

 Plulyrhynchus lanlhopygius, Spix, Av. Bras. II, pi. ix. 

 Ilab. — Coast region of Brazil, according to Burmeister, from whom most of the preceding synonyms and the indications of tho 

 species are cited. 



