ORNITHOLOGICAL EXPLORATIONS. 347 



and V. Schrenck usually mix such forms together under one name 

 which we regard as species or subspecies worthy of separate names 

 {cf. also the remarks above, on p. 345), So also in the i^resent case, as 

 the eastern Chelidones are lumped together as Hirundo rustica var. rufa. 

 Usually it is nearly impossible to extricate the observations belonging 

 to the different forms, but in this case the difterence between Ch. gut- 

 turalis and Ch. tytleci was too great for even v. Schrenck to ignore alto- 

 gether, though he hj no means suspects them of being separable, much 

 less understands the importance of keeping them separate*. 



Fortunately his remarks enable us to decide which forms he and Mid- 

 dendorff collected at two very important localities. Speaking of the 

 ^'-Hirundo rustica var. rufa^'' which he found throughout the Amur 

 Valley (Eeise Amurl. I, p. 387), he observes that it was "much paler 

 than the old male among MiddendorflTs specimens from Udskij Ostrog^ 

 and only slightly darker than the old male of the European Barn Swal- 

 low. * * * The black band of the fore neck is only narrow and con- 

 tains some rusty brown spots. "t 



This description is quite sufficient for identifying the Amur Valley 

 bird as Ch. gutturalis, while on the other hand, the remark plainly 

 shows that the bird Middendorff collected at Udskij Ostrog,at the mouth 

 of the Uda Valley, is Chelidon tytleri. This determination is extremely 

 interesting since the valleys of the two rivers Amur and Uda are close 

 together, only being separated by the Bureja Mountains, but the direc- 

 tion of the Amur and Ussuri is southern, while Uda comes from the 

 west. The Stanovoj Mountains, which until this point run close to the 

 shore of the Okotsk Sea, make here a sudden bend to the westward, lead- 

 ing over to Dauria and Transbaikalia. According to Middendorff (Ise- 

 piptesen Russl., p. 125) Vossnessenski met " Hirundo rustica var. rufa " 

 at Ajan. We also know that Ch. tytleri is common oq the western coast 



*That V. Schrenck writing as he did, before the theory of evolution was fairly 

 developed aud iinderstood, and before the recent theories of the bird migration, which 

 are so closely connected with the former, had been conceived, is perhaps not so very 

 surprising. That Taczanowski, however, still, in 1883, refuses to recognize the differ- 

 ence between gutturalis aud tytleri {- saturata) {cf. his foot-note on p. 356, Bull. Soc. 

 Zool. France, 1883, in regard to the latter form), and fails to see the necessity of 

 tracing the geographical distribution of each one separately, is a matter both of sur- 

 prise and regret. 



f'Viel bliisser als das alte Miinnchen unterden Middendorffschen Exemplaren voii 

 Udskoi Ostrog, und nur wenig dunkler als das alte Mannchen der europaischen Rauch- 

 chwalbe. * » » Das schwarze Band der Kropfgegend ist nur schmal und triigt 

 einige rostbraune Flecke." 



