FALCONIDAE. 



Of some eggs the markings bear (lie character proper to beauti- 

 fully marked biifeo-eggs, namely underlying and superficial spots, 

 each shading from dark to a lighter tint, wound mostly in a right- 

 handed spiral. 



RzEHAK mentions in his description of the characterizing features 

 of /HS//s-eggs : ,mit violettgrauen Schalenflecken (read: underlying 

 [brown] spots which show through violet grey), wekhc keinem Eie 

 fehlcn". That every nisus-Qgg bears spots on layer I is certain but if the 

 said writer meant to assert — as I suspect he did — that these 

 spots are visible on every egg, his assertion is not correct; they 

 frequently cannot be seen: this depends wholly on the greater or 

 smaller thickness of layer II. 



I do not wish to omit mention of the fact that Von Riesenthal') 

 saw at Chief-Forester Wiese's in Greifswald, a very interesting, 

 brownish coloured variety of nisus-egg; of this egg, therefore, as 

 in the case of the genera Faico and Ccrchncis, layer II must have 

 been covered by a diluted quantity of oorhodein. 



Morris mentions a set which consisted of 5 plain white eggs; 

 in these eggs, therefore, the spots on layer 11, and certainly those 

 on layer III, were probably absent. 



Mr. E Detaiers (Lingen on Ems, province of Hanover), with 

 whom I entered into correspondence in reference to an article -) 

 which he had published, informed me (in a letter of August 29, 

 1906) that in regard to Accipiter nisits he had found from experience 

 that the larger the number of eggs of a set is and the darker the 



') O. VON Riesenthal, Die Raubvogel Deutschlands (Cassel, 1876) p. 59, 

 footnote. 



-) Buteo buteo, Astur pahimbarius, Accipiter nisus et Syrnium aluco (In : 

 Zeitschr. f. Oologie unci Ornitholugie, XVI, p. 76). 



