966 Letters^ Extract.^!, and Notes. [Ibis, 



entered an interniitiable maze from which there is no escape 

 save to retreat and recognize all inconstant variations as 

 variations ot" species units. Furthermore, in the study of 

 bird migraiion, it is not trinomial, but the fact of geographic 

 variation that aids in determining migration routes. 



Engineers tell us that the strength of a structure is 

 primarily the strength of its foundation. The foundation 

 of the suhspecies is an unstable variation, and in conse- 

 quence the structure is collapsing. Hasten the day when 

 we shall view its ruins with the same complacency as we 

 view the ruins of the Quinary System. 



Yours truly, 



San Francisco, Leverett Mills Loomis, F.A.O.U. 



26 July, 1920. 



Birds of Texel. 



Sir, — To the list of birds found in Te.xel contained 

 in \)v. C. B. Ticehurst's valuable paper (Ibis, 1920, p. 361) 

 I can add four species. On the 8th of May, 1907, I 

 saw a Hoopoe on the wing. A (very) Mealy Hedpoll 

 (apparently a female) was feeding in some willows, eating 

 the catkins or something^ on them, on the 19th of May, 

 1908. I saw three Black-winged Stilts on one of the meres 

 near the west coast (where they had been seen the day 

 before) on the 14th of May, 1907; and on the same day, on 

 an adjoining mere, I spent some time watching a pair of 

 Black-necked or Eared Grebes, which I have no doubt were 

 nesting, or going to nest, in a big but thin reed-bed. They 

 were in full summer dress, and, to judge from the many 

 times the ordinary cry of blidder was uttered from the 

 inside of the reed-bed, as well as by the birds I watched, I 

 thought there were more Eared Grebes there. 



As to the birds mentioned in the paper referred to, 

 I should like to say that I saw Crested Larks in two places 

 near Hoorn on the 25th of May, 1908, and had no doubt 

 that this sedentary species was breeding there, although 1 



