22 



ARKV FÖR ZOOLOGI. BAND 12. N:0 7. 



however, to throw some scanty glimpses of light on a very 

 dark and, in spite of all recent work, still very unknown 

 field, and in such a case even the least contribution is of 

 interest. 



Explanation of Plates. 



Pl. 1. Hybrid Gulls, Larus fuscus ^ X L. leucopterus ?. To the 

 right in its first, to the left in its second year. 



Pl. 2. Hybrid Gull, Larus fuscus cT X i. leucopterus ?, immature 

 bird in its third year. Winter-plumage ^Vs 1915. 



Pl. 3. Hybrid Gull, Larus fuscus ^ X L. leucopterus $, adult bird, 

 only retaining some immature markings on the tail, July 1916.' 



Tryckt den 20 februari 1919. 



Uppsala 1919. Almqvist & Wiksells Boktryckeri-A.-B. 



