NATURAL SCIENCES OP PHILADELPHIA. 495 



transverse bars of dark plumbeous or slate; these bars widest on 

 the breast, but even here narrower than the white ; on the flanks 

 and crissum they are paler, very narrow, and distant. Wing, 

 6.50 ; tail, 6.30 ; culmen, .60 ; tarsus, 2.30; middle toe, 1.20. 



Remarks. This species most closely resembles 31. guerilla in 

 its plumbeous phase, to which it is so very similar that we had 

 referred it to that species, not making much, at the first com- 

 parison, of the smaller number of tail-bands. But after measuring 

 carefully all the specimens of 31. guerilla, and finding that the 

 minimum length of tail in that form is 6.90 inches, ran oingj thence 

 to 7.50, and always greater than the length of the wing, we were 

 quite surprised to find the tail of this specimen to be only 6.30 

 in length, or decidedly shorter than the wing, which, as were also 

 the other parts, was about as in the average of 31. guerilla. In 

 abbreviated tail it is like 31. concentricits, and it appears that Mr. 

 Salvin had referred it to that species, since the label bore in his 

 handwriting the name " 31. gilvicollisj' 1 as did also a true 31. cun- 

 centricus in the collection ; but it differs very essentially in the 

 relative length of the lateral toes, the outer one being decidedly 

 longer than the inner, instead of barely equal to it, or appreciably 

 shorter ; while the barred crissum and under wing-coverts dis- 

 tinguish it at a glance from that species. 



This may possibly be the 31. gilvicollis of Pelzeln 1 (loc. cit.), but 

 the latter is very much more likely to be the plumbeous phase of 

 31. ruficollis, called by Sclater and Salvin 31. leucauchen, and by 



1 " M. pileo, capitis et colli lateribus, nucha, dprso, uropygio aliscpie 

 supra cinereaceis, remigibus brunneis, parte basali pogoniorum internorum 

 albo transversim striatis, alarum tectricibus inferioribus albis, brunneo 

 transverse fasciolatis, gula albescente grisea, jugulo, pectore et abdomine 

 albis, dense brunneo transverse fasciolatis (fasciis 6-8 in singula pluma), 

 abdomine imo, corporis lateribus, tibiaruui plumis et caudse tectricibus in- 

 ferioribus ejusdem coloris fasciis rarioiibus, angustioribus, cauda? rectricibus 

 nigrescente-brunneis apicibus albis, fasciis transversis albis angustis tribus 

 sequidistantibus, rostro corneo basi flavo, pedibus flavis. Longit. 13^ 14 /r , 

 alffi 6, 9-10'", cauda? 6^-7", rostri a rictu 9-11'", tarsus 2", 3-4'". 



Avis juvenis differtis notaeo obscure brunneo, uropygii plumis punctis 

 albis notatis, genis brunneo et ochraceo variegatis, fascia transversa alba 

 utrique infra genas versus nucham ducta cum nucha? plumis albo-maculatis 

 collare interruptum formantibus, gula alba, gastrgeo pallide ochraceo fasciis 

 brunneis rnulto rarioribus et angustioribus, cauda? fasciis tribus interruptis 

 et passim obsoletis. 



