156 



THE OOLOGIST. 



diifei'ent from one another. All that 

 kept them from being rated as differ- 

 ent species was the fact that the.y 

 were known to intergrade near the 

 confines of their respective habitats. 

 As examples we will take birds. The 

 same facts, however ai'e applicable to 

 any other branch of the animal king- 

 dom, or even to plants. 



When the rioug Sparrows were care- 

 fully studied, it was found that those 

 living in one part of the country differ- 

 ed very much from those in some other 

 part. In the Eastern U. S. and as far 

 West as the Great Plains, the differ- 

 ences between individuals from differ- 

 ent parts was very trifling. They 

 would all answer to the same desci'ip- 

 tion. Their surroundings, their en- 

 vironment, was much the same in 

 every district and no barriers prevent- 

 ed a free migration from one part to 

 another. Why should they be differ- 

 ent? These sparrows were named 

 Melospiza fasciaia. 



But in Arizona and New Mexico the 

 surroundings wei'e different. The hot, 

 dry climate had changed the .color of 

 our little bird. The difference could 

 uot be called specific as on the borders 

 of their territory the differences be- 

 came less evident. They inter graded. 

 They were given the name Melospiza 

 fasciata fcdlax; retaining the generic 

 and specific names, but having the sub- 

 specific term added. * 



In Colorado, Utah and Northward, 

 they wei-e found to differ from the Ari- 

 zona variet}', as well as from the East- 

 ern form. They were named Melospiza 

 J'aseiata montana. 



It is not to be inferred that these 

 varieties are gradations between Mel- 

 ospiza fasciaia and some other bird. 

 .They ai'e only the subjects of variations 

 between groups of individuals of the 

 same species. . These groups have been 

 subjected to different environments. 

 Any one of these might be called "typi- 

 cal" and the others "varieties." The 



fact that they intergrade shows us that 

 the}' are but varieties of the same spec- 

 ies. 



There has been some condition or set 

 of conditions active enough to start 

 them in some particular line of varia- 

 tion. Why can not those conditions 

 carry them on in these variations? 

 They certainly will unless the subject 

 has become perfectly adapted to its 

 surroundings. 



The better the two varieties become 

 adapted to their environments, the 

 more different will they become, be- 

 cause their environments differ. Some 

 of these are specifically different. The 

 only thing that prevents their rating as 

 different species is the fact that they 

 intergrade on the borders of their ter- 

 ritories. If something should trans- 

 pire to more completely separate them 

 then they would be known as distinct 

 species. S. 



* Melospiza fasciata. Eastern U. S. toPlaius. 



Melospiza fasciata fallax, New Mexico and 

 Arizona. 



Melospiza fasciata i/ionta/Hi. Uolorado. Utah 

 and northward. 



Melospiza fasciata luermaiiiiii. Interior 

 Southern Cat., East into Nev ida. 



Melospiza fasciata samueiis. Coast of Calif. 



Melosjnza fasciata yiittafa. Coa^t Of Orejioii 

 and Washington. 



Melospiza fasciata niti/ia. Coast of Brit. 

 Col., north to Sitka. 



It is also to note the series of Shorf> Larks, 

 with their localities and the measurements of 

 types. 



Olocoris alpestris. W, 4.44. T. 3.02. Bill, .''/. 

 Northwestern N. A.. Lab. and Greenland. 



O alpestris prat icola. W. 4 17. T.-J.93. B. .88 

 Upper Miss. Valley. 



0. alpesfris leucoUema. W. 4.39 T. ii.'.trt. B. 

 .89. Brit. America and Alaska. 



alpestris arenicola. W, 4.27. T. H.-J^>. B. 

 .84. Gt. Basin and Rocky Mts. 



0.- alpestris giraudi. VV. 3.8r. 2'. -ir,!., B, 

 .80. Eastern Texas. 



O. alpestris chrysolaema. W. 3.98. T, 2.91. B. 

 .S3. Mexico. 



0. alpestris rnben". W. H.r>i, T. 2.71. B. .77. 

 California. 



O. alpestri>< .ylriijata. W. 3.99. T, 2.7.5. B. .76. 



