SYLV1IDAE. 



Through both the texture of the shell and the exceptional 

 ground colour, the genus Hypolais stands completely isolated. 

 Klhinschmidt x ) sees in the black speckles which often occur 

 concentrically in the spots of Acrocephalus palustris a certain homoge- 

 neity with the markings of hypolais-eggs. These speckles are found, 

 however, in greater or smaller numbers in many other species with 

 spotted eggs, belonging to different Families; in the case of the 

 Sylviidae I find them on eggs of 5. sylvia, curruca, atricapilla, 

 simplex, Ph. sibllatrix, trochilus and collybita ; further on those of 

 A. arundinaceus and strepera ; and, finally, although in very small 

 numbers and minute in extent, on eggs of C. schoenobaenus. The 

 speckles in question which, in my opinion, consist of pigment 

 thickened locally, varying greatly quantitatively, and only conglutinated 

 in a slight measure with the uppermost layer of the shell, form 

 therefore, no specific characteristic of A. palustris through which 

 hypolais is alleged to show oological resemblance to that very species. 



In the genera Calamodus and Acrocephalus the species aquatica 

 and schoenobaenus on the one side and palustris, strepera and 

 arundinaceus on the other belong together oologically; the last 

 named species stands closest to palustris. The existence of some 

 relationship between Acrocephalus and Sylvia — formed by certain 

 types of 5. sylvia and the palustris-group — has already been 

 pointed out above. 



As regards the genus Locustella I can point to no oological relation- 

 ship whatever between it and any one of the other genera of the Family ; 

 this genus stands by itself in both the texture and the marking of 

 the eggshell. Thienemann considered that there was a certain relation- 

 ship in texture between naevia and A. strepera, and between luscini- 



') Journal fur Ornithologie, 51 (1903), p. 483. 



