INSESSORES. SAXICOLINA. 179 



is divided into five primary groups or circles, each returning 

 into itself: viz. 1st, The subfamily Saxicolina, represented 

 by the genus Saocicola of Bechstein, which also from its 

 near affinity to the Rock Thrushes (genus Petrocincla, Vig.) 

 becomes one of the links between the Sylviada and Meru- 

 lidtE; 2dly, PMlomelina, of which the Nightingale may be 

 taken as a typical example, the members of which are most 

 of them remarkable for their vocal powers ; 3dly, Sylviana, 

 the pre-eminently typical group of the whole family, and of 

 which the Gold-crests (genus Regulus) are by Mr Swain- 

 son considered the type ; 4thly, Pariana, represented by 

 the genus Parus ; and, 5thly, The subfamily Motacillina, 

 of which the genus Motacilla of Latham is to be considered 

 the typical form. 



Subfamily SAXICOLINA. 



This subfamily, forming one of the aberrant groups of 

 the Sylviadae, contains, besides the Chats, or the typical 

 genus Saxicola (Bechst.) that of Erytkaca (Swains.), of 

 which our Redbreast is the type, and represented in America 

 by the Bluebirds belonging to Swainson's genus Sialia. 

 The Redstarts (gen. Phcenicura, Swains.) also appear to 

 have their station here rather than in the subfamily Philo- 

 melina, to which, however, they directly lead the way ; and 

 the genus Petrdica (Swains.), an Australian group, repre- 

 sented by the Muscicapa Erythrogustra of Latham, is also 

 associated with the present subfamily, but stands, as it were, 

 upon the confines of it ; and by the depression of the basal 

 part of the bill and hairy gape, conducts us, by its affinity 

 to the genus Setophaga (Swains.), to the subfamily Pariana, 

 as well as to the Flycatchers of the Fissirostral tribe. The 

 members of this subfamily, from the comparative length of 

 the tarsus and structure of the feet, are calculated for active 

 movements upon the ground, as well as for perching, and 

 many of the typical species are the inhabitants of downs and 



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