226 HVLTOTA. 



while the hreadth of the hill at its hase indicates its 

 insectivorous habits : its apparently anomalous struc- 

 ture, in other respects, is explained by the situation 

 it holds as the tenuirostral type of its own genus. 

 Hence its bill is the longest, and, like that of 

 Monachus, it is considerably compressed ; by the 

 absence of bristles, and by the thick feathers on the 

 rump, it preserves its analogy to the Cellepyrina^ 

 or caterpillar-catchers, without diminishing its 

 affinity in other parts of its structure to Musci- 

 capa, or its analogy in point of colour to Platys- 

 tera. Such are the conclusions we have come to 

 after some years reflection, and which we have 

 elsewhere intimated*. At present we know but of 

 one species; the sexes of which, unlike all the 

 other types of Muscicapa, differ as remarkably in 

 colour as do those of its prototype Platystera. And 

 the student will remember, that the tenuirostral 

 types are always those which have the most marked 

 difference in the plumage of the sexes. The whole 

 of the Ampeiidce, the order Grallatores, and the 

 tribe of Tenuirostres, not to mention the Orioles, 

 Psariance, and several others of minor note, are 

 convincing proofs of this general law. It is well 

 known, again, that nearly all tenuirostral types have 

 the longest bills among their congeners : witness the 

 humming-birds and the whole order of waders. We 

 find this analogy, therefore, ^reserved in the present 

 family ; for this is a peculiar characteristic in Psaris^ 

 Parspicilla, Monacha, and Hyliota, groups of dif- 

 * Classification of Birds, ii. 



