14 TROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



Such is, ill brief, the history of the case. The poiut at issue, however, 

 is whether specimeus of this species from the Kio Grrande Valley in 

 Texas are to be referred to mexicanus proper or to an assumed race, 

 ^^enjthrocercus.''^ The species was originally introduced to the United 

 States fauna nnder the name " M. crlnitus erythrocercus (Scl. & Salv.) 

 Cones " (Bull. U. S. Geol. & Geog. Surv. Ter., Vol. IV, No. 1, p. 32), and 

 was subsequently mentioned by the present writer as " M. erythrocercus 

 var. coopcri " (Proc. U. S. Xat. Mus., I, 1878, p. 138), both of which I 

 believe to be incorrect — the former on account of the reference of the 

 sptcies to M. criiiitus, and, probably, in the use of the name erythrocer- 

 eus Instead of mexicanus; the latter, because erythrocercus is the subse- 

 quent name, and cannot, therefore, be used for the specific designa- 

 tion, while cooperi is also very doubtfully referable to this species. In 

 order, however, to present the case as briefly and clearly as possible it 

 will be necessary to discuss the several points separately. 



First, as to the reference of this species to crlnitus : I do not see how 

 this can possibly be done without bringing in also 3f. cinerascens and 

 M. stolidus (see Hist. N. Am. B., Vol. II, p. 331); and even then I 

 much doubt whether crinitus and mexicanus ever intergrade, since I 

 have examined many scores of si)ecimens, but have yet to find a speci- 

 men that is truly intermediate.* There is, however, in Southwestern 

 Mexico a very small race of mexicanus, which can be distinguished from 

 cinerascens only by the extension of the rufous of the retvices to the 

 extreme tip of the inner web, they being in every other respect appa- 

 rently quite identical. There are several such examples in the national 

 collection, obtained in Tehuan tepee by Professor F. Sumichrast. 



Second : It is much to be regretted that neither Dr. Kaup nor Dr. Sclater 

 give measurements of the type sx)ecimens of T. mexicanus, since we 

 might then readily determine whether this name belongs to the large 

 or the small race of the species as occurring in Mexico. Since, however, 

 Dr. Sclater remarks that "it (the said type) is certainly rather smaller 

 in dimensions than two of my skins of this species {i. e., "If. cooperi,'''' 

 Baird), and has the bill smaller"; and that "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," it appears very evident that Kaup's T. mexicana was not based 

 on one of the very large individuals of this species, but one of medium 

 size, corresponding to the Rio Grande specimeus. Further than this, 

 the individual variations among Mexican specimens of this species affect 

 only the size and proportions, not colors — at least not to any especially 

 noticeable extent. 



Third : I find upon re -examination of all the material in the national 



* In Hist. N. Am. Birds, Vol. II, p. 331, we predicated the intergradatiou of these 

 two species on the characters of au individual from Nicaragua, which, however, Dr. 

 Coues (Pr. Philad. Acad. 1872, p. 68) says, and which I also now believe, is not dis- 

 tinguishable from M. crinitus. 



