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Show 84 MR. P. L. SCLATER ON TWO TYRANNUL_E. [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. [Received January 13, 1871.] Dr. Kaup's Tgrannula 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 31. 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 Association to Liverpool. Indeed Kaup says (I. s. c), "Mr. Woll-weber sent m e this species, which I also found in the British Museum." 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 exhibit. 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. laivrencii, inasmuch 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 m y skins of this species, and has the bill smaller. But a third specimen in m y 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 Bairdf. * Obtained at Atlisco, in the State of Puebla, by Boucard. t What Tyrannula cooperi, Kaup, is (which Prof. Baird'believed to be this Myiarchus) does not now much signify. The original Muscicapa cooperi of JVuttall 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 probabfy not Muiar-chus cooperi of Baird. J y |
