135 Mr. H, E. Dresser. 



further another, M. solitarius, hoth of which differ in having: 

 rufous on the under parts, and must be reckoned as climatic 

 forms which have attained the rank of distinct species. 



Most birds which are non-migratory, or which, like the 

 Dippers, only travel from stream to stream, or only wander 

 over a limited area, are less subject to variation, or when 

 variation does exist it is so constant as to raise them to distinct 

 species. Hence I have treated the European Dippers as being 

 referable to three species, Cinclus melanogaster, Cinches 

 aqtiaticus, and Cinclus albicollis, for though the differences are 

 slight they are constant, and each species has its distinct 

 range. Amongst the Saxicolince one also finds several 

 instances where forms, though closely allied, should be treated 

 as distinct species, for the differences are constant, and each 

 form has its distinct range ; thus Saxicola rufa, though closely 

 allied to Saxicola melanoleuca, always has the black on the 

 throat covering a smaller area, and it inhabits south-western 

 Europe, whereas Saxicola melanoleuca only inhabits the 

 eastern portion of the Palaearctic region and western Asia. 

 The common Stone Chat, Pratincola rubicola, is replaced in 

 eastern Europe and Asia by a very closely allied, more brightly 

 coloured form, Pratincola maura, which may always be 

 distinguished by the upper tail coverts being uniform white 

 and not marked with colour ; and again in the south-eastern 

 portions of the western Palasarctic regions, and in western Asia, 

 a third form, Pratincola hemprichi, is found, which has the 

 basal two-thirds portion of the tail pure white. Our common 

 Redstart is replaced in south-eastern Europe and Asia Minor 

 by a very closely allied form, Ruticilla mesoleuca, which, 

 besides other slight differences, always has a conspicuous white 

 speculum on the wing, and our common Robin, Eritliacus 

 ruhecula, has, as one goes further east, two very close allies, 

 which must, however, be treated as two distinct species, viz., 

 Eritliacus hyrcanus, inhabiting Persia, and differing in having 

 the tail feathers broadly margined with bright ferruginous, and 

 the red on the throat and breast much richer in colour, and 

 Eritliacus akahige, inhabiting Japan, which has the red on the 

 breast, bordered below with a band of blackish, and the flanks 

 greyish black. 



Of the Blue-Throated Warblers there are two distinct 

 species, which, by many naturalists, have been united, but, I 

 feel convinced, without good reason, for they have quite 

 distinct breeding ranges, and, furthermore, have never, I believe, 

 been known to interbreed. One of these, Cyanecula Suecica,. 

 has a patch of red in the middle of the blue throat, and 

 inhabits eastern Europe and western Asia, breeding nume- 

 rously in Scandinavia and northern Russia, whereas the other, 



