1S90.] ALLEN on the Recognition of Geographical Forms. c 



American birds. As some hard-and-fast line in respect to sub- 

 species was necessary it was very properly agreed by the Com- 

 mittee that no species should be reduced to a subspecies except 

 on proof of intergradation. This kind of proof is sometimes 

 lacking- where its existence is a theoretical certainty. Yet it 

 seemed better to leave such questions open to be settled by a 

 later increase of material. 



The work of the A. O. U. Committee on the [nomenclature 

 and status of North American birds yielded as satisfactory results 

 as could have been anticipated, nearly nine-tenths of its de- 

 cisions being reached by practically unanimous consent. The 

 outcome of its deliberations, as embodied in the A. O. U. Code 

 and Check-List, has well stood the test of time, there having 

 been found thus far very few cases where subsequent discoveries 

 have necessitated any revision of the Committee's decisions. A 

 few forms then considered as ineligible to subspecific rank, and 

 therefore rejected, have since been admitted, in consequence of 

 the acquisition of material from new localities rendering their 

 proper status more evident ; while others have been described 

 and added to the list. Some of these later discoveries have proved, 

 indeed, little less than startling. These facts, and the very great 

 increase of material during the last five \ ears, have had possi- 

 bly a too stimulating effect; they have unquestionably started the 

 pendulum again in the direction of finer discriminations and exces- 

 sive splitting. The majority of the old A. O. U. Committee, the 

 authors of the Check-List, will doubtless now admit forms to sub- 

 specific rank they would not have admitted in 1S84, had they 

 been then placed before them. They certainly know much more 

 about North American birds at present than they did five years a°-o, 

 but is their judgment as sound and are their tendencies as ration- 

 ally conservative? 



If any be without sin, let him cast the first stone. Conscious of 

 my own changed tendencies, it has seemed to me well to raise the 

 above question for brief consideration, since it can do no harm to 

 survey ffre field calmly and take note of the present drift in respect 

 to a very important subject. 



Recent investigations have taken me over fields I worked, with 

 some care, ten to fifteen years ago. In the meantime material 

 has greatly increased ; series of specimens have been obtained 

 from localities then unknown ; thus I find myself lookino- at 



