NATURAL SCIENCES OF PHILADELPHIA. 499 



Micrastur concentricus of Pelzeln; but whether that gentleman 

 is right in his identification of Lesson's description, we are not 

 able to decide ; but, for the benefit of those who may have an 

 opportunity to examine Lesson's type, we will say, that, should 

 it have the outer toe not perceptibly longer than the inner, 1 the 

 conclusion is correct, for the bird now under consideration differs 

 essentially from every other one of the genus in this remarkable 

 respect. Should there be no way of deciding this point by exami- 

 nation of Lesson's type, the species might be called M. concentri- 

 cus, Pelzeln, which name we feel justified, under the circum- 

 stances, in adopting. Pelzeln's description of this species is as 

 follows : 



" M. pileo, capitis et colli lateribus, nucha, dorso et uropygio 

 schistaceis, alis supra concoloribus sed magis brunneseentibus, 

 remigibus brunneis parte basali pogoniorum internorum albo 

 transverse fasciolatis, gula grisco-alba, jugulo, pectore et abdo- 

 mine albis brunnes transverse fasciolatis (faciis 5-t in singula 

 pluma), abdomine imo, corporis lateribus et tibiarum plumis 

 ejusdem colons fasciis rarioribus angustioribus, belricibus caudal 

 inferioribus albis haud fasciatus, caudse rectrieibus nigres centibus 

 apicibus albis fasciis transversis angustis albis duabus, una 

 versus basin altera medium collocata, vel (solummodo in indi- 

 viduis nonnullis adultis) fascia unica post medium sita, rostro 

 corneo interdum basi, interdum apice flavo, pedibus flavis. 

 Longit 13| usque 14", alae Gf-I", caudse 6^, rostri a rictu 10- 

 12'", tars. 2" 3-4'". 



" Avis junior differtis fascia transversa albo brevi utrinque infra 

 genas versus nucham ducta, pectore et abdomine ochraceo-lavatis 

 fasciis brunneis multo rarioribus et angustioribus, abdomine infe- 

 riore, corporis lateribus et tibiarum plumis fasciis nullis." [Orn. 

 Nov. 1865, 9.] 



There is but one feature in Pelzeln's description of his M. con- 

 centricus which does not accord with our concentricus, and that 

 is the number of bands on the tail, which are stated to be from 

 one to two, besides the terminal one, whereas in the specimens of 

 our bird which we have seen, amounting in all to eight examples, 

 the number varies from three to four ! Should it be possible that 

 there are two species with immaculate white lower tail-coverts, it 



1 The claw is not included ; see figs. 8 and 9, pp. 481, 482. 



