— 42 — 



Biddulph (J.). The Black Grouse in Herefordshire. (The Zoolo- 

 gist. p. 2852. 1850). 



Biom (G. M.V Beschreibung eines ganz hellgrauen oder bey- 

 nahe weissen Birkhuhns, Tetrao tetrix Q±. (K. Schwed. Abhandl. 

 p. 255. 1785). 



Grotch (W. D.). Black Gi^ouse in Devonshire. (The Zoologist. 

 p. 2652. 1850). 



Gadamer (H.). En Orrjagt som var dyr. (Jâgarefôrb. N. Tidskr. 

 p. 35. 1864). 



Gibson (B.). Tetrao tetrix. (Afin. Mag. N. H. IX. p. 438. 1842. 



Hagstrôm (J. 0.). Versuch Birkhàhne. mit allerley Gewàchsen 

 und Laube. zu futtern. (K. Schwed. Ak. Wiss. Abh. p. 139. 1751. 

 — K. Vet. Ak. Eandl. p. 132. 1751). 



King (E.). The Black Grouse near Lynn (The Zoologist. p. 3476. 

 1852). 



Mw. Orrjagt pa Gottland (Jâgarefôrb. N. Tidskr. p. 193. 1865). 

 Morris (B. R.) The Black Grouse, Tetrao tetrix. (The Zoologist. 

 p. 2852. 1849). 



Newton (A.). Note on the Black Grouse at Elveden. (The Zoo- 

 logist. p. 794. 1844). 



Parelius (Gram.). Om Orsakerna till Orrarnes minskande 

 antal. (Jdrefôrb. N. Tidskr. p. 184. 1876). 



Powys (T. L.). Black Grouse in Northamptonshire. (The Zoolo- 

 gist. p. 3278. 1851). 



Stevenson (H.). Varieties of Black Grouse and Hybrid between 

 Blackcock and Capercally. (The Zoologist. p. 6243. 1858). 



Sundevall (G.). Hybriditeter ai Orre med fiera foglar. (Oefvers. 

 K. Vet. Ak. Fôrh. p. 125. 1845). 



— Om sterila honor af Orre och Bons (Ibid. p. 130). 



Thompson (W.).On Hybrids produced inawild State between 

 Tetrao tetrix and Phasianus colchicus . (Mag. Zool. Bot. I. p. 450. 

 1837. — Isis p. 516. 1844). 



Tobias(R.). Eine hahnfederig werdende Birkhenne. (Nauman- 

 nia II. p. 88. 1854). 



