84 MR. P. L. SCLATER ON TWO TYRANNULA. [Jan. 17, 



6. Notes on the Types of Tyrannula mexicana of Kaup, and 

 Tyrannula barbirostris of Swainson. By P. L. Sclater, 

 M.A., Ph.D., F.R.S. 



[Keceived January 13, 1871.] 



Dr. Kaup's Tyrannula mexicana, shortly described in this Society's 

 'Proceedings' for 1851 (p. 51), has long been a stumbling-block 

 to those engaged on American ornithology. I was originally inclined 

 to believe it to be the same as Myiarchus lawrencii (see P. Z. S. 

 1856, p. 296, etCat. A. B. p. 233). Prof. Baird has identified it 

 with M. cinerascens, Lawrence (cf. B. N. A. p. 179); and his view 

 has been usually followed by American naturalists. 



Prof. Baird and Mr. Lawrence have both lately applied to me to 

 clear up this point, and have supplied me with skins of the allied 

 species for comparison with Kaup's type, which they believed to be 

 in the Derby Museum, Liverpool. This, however, is not the case, 

 as I ascertained last summer during the visit of the British Asso- 

 ciation to Liverpool. Indeed Kaup says (I. s. c), "Mr. Woll- 

 weber sent me this species, which I also found in the British Mu- 

 seum." In the British Museum I ascertained that Kaup's type, 

 if present, was not marked, and was accordingly forced as a last 

 resource to apply to Dr. Kaup himself. Dr. Kaup, with his 

 usual kindness, immediately forwarded to me the desired specimen 

 from the Grand-Ducal Museum of Darmstadt, which I now ex- 

 hibit. 



Taking as a guide Prof. Baird' s diagnosis of the difficult species of 

 this group in his standard work on North-American Birds (p. 177), 

 it will be seen at once, on examination of the typical specimen of 

 Tyrannula mexicana, that it cannot be referred either to Myiarchus 

 mexicanus (i. e. M. cinerascens of Lawrence) or to M. lawrencii, in- 

 asmuch as it has the "inner web of the tail-feathers broadly rufous 

 to the extreme tip " — thus coming into Sect. A of the genus, which 

 includes only M. crinitus and M. cooperi. Further comparison 

 leads me to believe that the bird is really undistinguishable from M. 

 cooperi, as here described by Baird. It is certainly rather smaller 

 in dimensions than two of my skins of this species, and has the 

 bill smaller. But a third specimen in my collection*, which I also 

 refer to the (so-called) M. cooperi of Baird, agrees very well with 

 it in general dimensions, and has the bill even slightly smaller. I 

 do not, therefore, hesitate to decide that Tyrannula mexicana of 

 Kaup is identical with Myiarchus cooperi of Bairdy. 



* Obtained at Atlisco, in the State of Puebla, by Bouoard. 



t What Tyrannula cooperi, Kaup, is (which Prof. Baird believed to be this 

 Myiarchus) does not now much signify. The original Muscieapa cooperi of 

 Nuttall is certainly Contopus borealis {vide Baird, B. N. A. p. 188). But it is 

 not to be supposed that Prof. Kaup would make two species of the same bird in 

 the same paper. Therefore Tyrannula cooperi of Kaup is probably not Myiar- 

 chus cooperi of Baird. 



