118 LIST OF DIURNAL BIKDS OF PKET. 



I have not been able to ascertain with certainty the im- 

 mature plumage of this race of Micrastur ; but I have seen 

 specimens from Bahia, much resembling the young of 

 M. guerilla, which I believe to be immature examples of the 

 bird now under consideration. 



Specimen No. 2 in the above list is one of those alluded to 

 by Messrs. Sclater and Salvin in the P. Z. S. 1869, p. 367, 

 as a specimen "not quite mature" of " Mici'astur leucau- 

 chen-/' but I am unable to accept this identification, as I am 

 decidedly of opinion that TemmincVs plate of the bird to 

 which he gave the name of " Falco leucauchen" represents 

 an immature example of M. rtificoUis\ and the present bird 

 appears to me to be the adult stage of a species, or at least 

 of a subspecies, distinct both from M. ruficollis and from 

 M. guerilla. 



Nos. 1 and 2 in my list have both been examined by 

 Mr. Ridgway, who has ticketed them " M. ruficollis, gi-ey 

 phase, adult,""^ and has described one of them as the " plum- 

 beous" phase of that species at p. 492 of his very valuable 

 monograph of the genus Micrastur, published in the ' Pro- 

 ceedings of the Academy of Natural Sciences of Philadelphia' 

 for 1875. My objection to this solution is chiefly geogra- 

 phical, as I have never seen the typical M. ruficollis (regarded 

 by Mr. Ridgway as the rufous phase of that species) from 

 any locality further west than the island of Trinidad, whereas 

 the bird which I am considering extends its range as far 

 westward as the United States of Colombia. 



I therefore look upon this race as a subspecies of M. gue- 

 rilla, intermediate between that species and M. ruficollis ; and 

 as the coloration of the jugulum is the point of distinction 

 between it and M. guerilla, I would propose for it the sub- 

 specific name "jugularis.'' 



For comparison with the measurements given above I may 

 quote the following, which I have taken from twenty-two 



' In my Notes on M. 7-vJicollis I expressed an opinion that this figure 

 represented an '^ immature female" of that species ; but I now believe that 

 no difference of coloration exists between the sexes. 



