On a new genus of Falconidce, 385 



ON A NEW GENUS OF FALCONIDiE. 



In one of the preceding numbers of this Journal,* where I at- 

 tempted to give a sketcli of the groups of the Falconidce^ I ex- 

 pressed my doubts whether two species belonging to the sub- 

 family of the Kitesy and nearly related to Eianus, Sav., the Falco 

 furcatus of Linnaeus, and the Falco Riocourii of M. Vieillot, ex- 

 actly corresponded with the characters of that genus. At the 

 time when I drew up the sketch, I had not the means of making 

 that accurate examination of these species which was necessary 

 for determining the point. The two birds however have since 

 come within my reach. Dr. Such, whose extensive researches in 

 Brazil have enriched science with so many important acquisitions, 

 has kindly presented me with a beautiful specimen of the F.fur- 

 catusy which he brought from that country : and I am indebted to 

 Mr. Leadbeater of Brewer Street, the value of whose collections 

 in Ornithology is equalled only by his liberality in opening them to 

 science, for an opportunity of comparing a fine specimen of JP, 

 Riocourii with the conterminous species. From the examination 

 which I have thus been enabled to make of these birds, it appears 

 to me that they do not sufficiently accord with Elanus to be ad- 

 mitted into the same genus. They have not the cylindrical 

 ungues of that group ; a character, which serves so much to dis- 

 tinguish it among the birds of the family, and which appears to 

 form a very decided ground for separation from the rarity of its 

 occurrence, two groups only, Pandion and Elanus^ having been 

 as yet observed to possess it. The tail also of the two birds in 

 question is considerably forked, while that of Elanus exhibits but 

 an approximation to the same form, or rather the first deviation 

 from the even tail of the preceding subfamily. Thus compared 

 with Elanus they seem to hold a distinct and a higher station in 

 the present subfamily. And while Elanus seems to hold its sta- 

 tion at the first entrance into the group, they most probably will 

 be found to form the typical species of it, in consequence of the 

 extreme developement of the forked tail ; which, it may be re- 

 membered adds strikingly to the powers of flight in the Kitesy 



* Vol. I. p. 333. 

 Vol. II. 2 b 



