14 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. © 
Such is, in brief, the history of the case. The point at issue, however, 
is whether specimens of this species from the Rio Grande Valley in 
Texas are to be referred to mexicanus proper or to an assumed race, 
“erythrocercus.” The species was originally introduced to the United 
States fauna under the name “ I. crinitus erythrocercus (Sel. & Salv.) 
Coues” (Bull. U. 8. Geol. & Geog. Sury. Ter., Vol. IV, No. 1, p. 32), and 
was subsequently mentioned by the present writer as “ M. erythrocercus 
var. cooperi” (Proc. U. S. Nat. Mus., I, 1878, p. 188), both of which I 
believe to be incorrect—the former on account of the reference of the 
species to MM. crinitus, and, probably, in the use of the name erythrocer- 
cus 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 erinitus: I do not see how 
this can possibly be done without bringing in also MM. cinerascens and 
M. stolidus (see Hist. N. Am. B., Vol. Il, p. 331); and even then I 
much doubt whether crinitus and mexicanus ever intergrade, since I 
have examined many scores of specimens, 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 Tehuantepec by Professor I’. Sumichrast. 
Second: Itis much to be regretted that neither Dr. Kaup nor Dr. Sclater 
give measurements of the type specimens of 7. mexricanus, 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. Selater remarks that “it (the said type) is certainly rather smaller 
in dimensions than two of my skins of this species (i. e., ‘J. cooperi,” 
Baird), and has the bill smaller”; and that “a third specimen in my 
collection, which I also refer to the (so-called) JL. cooperi of Baird, agrees 
very well with it in general dimensions, and has the biil even slightly 
sinaller,” it appears very evident that Kaup’s 7. mexicana was not based 
on one of the very large individuals of this species, but one of medium 
size, corresponding to the Rio Grande specimens. 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 intergradation of these 
two species on the characters of an 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. 
