126 



and plumbeous plumages, sliow rusty borders to the feathers of the 

 upper parts, while besides the texture of their plumage leaves no doubt 

 that they are very young birds in their first dress. 



Both adult and young exhibit the usual individual variation ; the 

 former varying in the greater or less bluish cast to the back and the 

 bars nuderueath, the degree of blackness in the color of the pileum, and 

 the former exhibiting tints variously intermediate between the rufous 

 and brown phases. There appears to be no well-marked sexual differ- 

 ence in plumage at any age, though the adult males seem to be rather more 

 plumbeous than the females. 



The proper specific name for this species is involved in considerable 

 doubt. Strickland is, we believe, the only one who has identified it 

 with the Falco mperciViosus of Linmeus ; other authors having, for 

 some reason, we know not what, discarded this name, and taken that of 

 Falco thius Latham, as the first designation of the species. So far as 

 the original descriptions are concerned, both of those quoted are ex- 

 tremely inaccurate, and disagree in very important respects with the 

 characters of the bird under consideration; but if there is no other clue 

 to what species were meant by these authors than their diagnoses, 

 Latham's description is much more inapplicable than that of Linnoeus. 

 It is as follows, the points of disagreement being italicized : — 



" F. pedibus flavis, corpore cinereo-fusco, subtus albido fasciis nigri- 

 cantibus, rertice albido. Tiny Falcon, Lath. Synop. sup. p. 39, Habitat 

 in Cayana ; inter minimos numerandus; ab apice rostri ad basin caud;ie 

 uncias sex tantum implens.'' 



This is at best a very poor diagnosis of the species under considera- 

 tion ; since, if this were the bird described, it is difficult to see why a 

 bird which invariably has a uniform black or dusky vertex should have 

 this portion described as white! 



Linnseus describes his F. supcrciUosuft as follows : — 



" F. cera pedibus palpebrisque luteis, corpore fusco albido undulato, 

 remigibus ferrugineis nigrofasciatus. Habitat in Surinamo. Dahlberg. 

 Magnitudo Picfe. Corpus supra fuscum, subtus totum etiam femori- 

 bus confertim nigro undulatum. Remigcs ferruginefc fasciis nigris plu- 

 ribus ] sed secuudariic margine posteriore albido. Cauda nigra fasciis 

 duabus latis & apice cinereis. Crissum album, strigis aliquot nigris. 

 TJropyghim alio nigroqne rarium, Supercilia subtus nuda, prominula. 

 Lora setis nigris patentibus. Eostrum & ungues nigri. Tectrices alarum 

 inferiores albfe lineolis tenuissimis nigris." 



This description is, in the main, a sufficiently accurate diagnosis of the 

 j)resent species in the transition-stage, or in moulting from the ferruginous 

 plumage, which sometimescharacterizestheyouug,into the adult plumbe- 

 ous stage, remnants of the first dress being the ferruginous remiges, as 

 described. But the clause " rump varied with black and white " is mani- 

 festly not a character of the present species, in which this part is 

 uniform slaty, with, however, an indistinct white spotting beneath the 

 surface, to be seen only upon disturbing the feathers. But this dis- 

 crepancy is trifling compared with that in Latham's description of his 

 Falco tinus, and, unless there is a better reason than we know of, we 

 cannot see why Linnaeus' name siijierciUosits should not be preferred. 



In case both these names be rejected on account of the reasons stated, 

 Sparvius sv.hiiger Vieillot would be unobjectionable, since the type has 

 been fully identified with this species by Pucheran. 



