NATURAL SCfBNCES OP PHILADELPHIA. 41 



figures and diagnoses of the various authors who hare treated of this 

 bird has shown that there are assigned to yEghthus Holhblli, as dis- 

 tinctive characters, exactly those differences from the linarius which exist in 

 the specimen's under consideration, — viz. : larger size, larger, more elongated 



Sight yellow bill, and larger gular spot. I think there can be no reason- 

 oubt that these specimens represent in North America the form long 

 ized in Europe under the name of ^'Ei/iothns RilhdlH. 



If this be the case, next comes the question, what rank are we to accord to 

 this form. Is it to be looked upon as an accidental variation from the type, — 

 as a well marked variety, — or as a distinct species ? Brehm was the first to 

 proclaim it as distinct, and give it a name. Temminck, S<-hlegel, Bonaparte, 

 and other authors, — who are rather more orthodox in thinr ideas of a species 

 than is Brehm, — have always inclined, more or less decidedly, to the opinion 

 that it is rather a race or sub.species of A. linarius. The fact of there being a 

 complete gradation towards the linarius, has not escaped attention, and has 

 been a powerful argument against according to it full specific rank. For my 

 own part, though unable to demonstrate tlie point incontrovertibly, I am in- 

 clined to reiterate still more strongly the doubts expressed in my Monograph, 

 as to the propriety of separating it from the linarius. 



Pursuing this question of the variations whi^h A. linarius presents, we find 

 another species, '— .4. rufescms, — which ha»never been able to fully vindicate its 

 claims to specific distinction. First introduced by Vieillot, its existence was 

 strenuously denied by Temminck, doubtfully regarded by Bonaparte and 

 Schlegel, and admitte^l by Cabani-! and others. I have always entertained 

 strong doubts as to its validity. The characters assigned are slight enough ; 

 and that they exhibit a gradation towards A. linariua, is admitted even by 

 those who contend for its separation i1k>va. that species. In examining two 

 hundred or ilnore specimens, I find many individuals, fully as small, in fact 

 and with asi much of a reddish tinge, as sp cimens from Europe labelled " r;/- 

 fp.scens " by good authority. 



The existence, then, in North Ameri(^ of these two races, or species, which 

 ever they may be, the one larger'and the otlirti- smaller tlian the typical lina- 

 rius, ma}^ be considered as exceedingly probable, if the fa'ct be not actually 

 demonstrable. As a sort of negative argument, I may remark, that one 

 might naturally look for their occurrence in this country as the typical lina- 

 rius from Europe is absolutely identical with our own. 



^■Egiothus ruf'escens and A. Holholli, compared with A. exilipe":, afford a good 

 illustration of the limits between which a species may vary from its normal 

 type ; while another species, looking at first glance more like this type than 

 do either of its extremes, is permanently distinct. 



I have no reason to change any of the views expressed with regard to three 

 new species I have introduced. Additional specimens confirm tiie position as- 

 sumed, especially regarding A. exilipet. I miy here, however, correct a 

 typographical error, wliich gives the date of the first iutroiucliou of A./usc.'s- 

 cens as " Aug., 1860," instead of " Aug., 18G1." 



