APPENDIX. 



499 



TYRANNULA PUSILLA, 



the breadth of the bill and the relative proportions in the length of the quill feathers deserve 

 attention. Mr. Audubon has figured, as new species, two or three small Fly-catchers, closely 

 resembling those of Wilson's and the two here characterized ; but as they are not described 

 with the requisite precision, it is impossible to determine what are their distinguishing cha- 

 racters. In 



TYRANNULA RICHARDSONII 



the bill is obviously longer, and the whole bird much larger. 



Family, SYLVIAD^. 



In reference to our remarks on the genus Erythaca, we feel persuaded that both Sialia 

 and Pefroica*, Sw., are types of form or sub-genera; Sialia being the Fissirostral type, the 

 great length of its wings, the emarginated lesser quills, its glossy plumage, and its migratory 

 habits, all confirming this view of its natural relations. The union of the Saxicolincs with 

 the Pariance, by means of the sub-genus Petro'ica, is so complete by the recent acquisition 

 of another new species, sent us from Van Diemen's Land, that we can scarcely determine to 

 which genus it truly belongs. 



Our suspicions regarding the situation of Hyliota have proved correct : it does not belong 

 to this family. By a singular chance, we detected among our friend Mr. Burchell's African 

 birds the Tenuirostral type of the Syhiance, perfectly corresponding with the same type in 

 the circle of the Merulince. This latter, we believe, only exists in the Paris Museum. 



Zool. Illust., Second Series, pi. 36. 



3 S 2 



