Mr. P. L. Sclater on two species of Ant-birds. 151 



On Two Species of Ant- birds in the Collection of the 

 Derby Museum, at Liverpool. By Philip Lutley 

 Sclater. 



1. Myrmeciza exsul, sp. nov. 



Obscure brunnescenti-castanea, Cauda concolore ; capite toto un- 

 dique et corpore infra ad medium ventrem nigris : ventre imo 

 crisso et hypochondriis dorso concoloribus : alarum tectricibus 

 minoribus nigricantibus ad apicem albo punctatis : campterio 

 albo : rostro nigro, pedibus obscure brunneis : periophthalmio 

 denudato. 

 Long, tota 5*0, aire 2*5, caudse 1*7, rostri a rictu 0*85, tarsi 1*2. 

 Hab. In isthmo Panama (Delattre) et in rep. Nicaragua. 

 Mus. Derbiano, sp. 4939, et Acad. Philadelph. 

 This species may be placed between M. hemimelcena and M. cin- 

 namomea in my arrangement. In colouring it somewhat resembles 

 the former, but it is of a much stronger build, and has no white 

 markings on the interscapularies. The bill is shorter than in 31. cin- 

 namomea, but the form otherwise nearly similar. The single spe- 

 cimen in the Derby Museum is marked with one of Delattre' s tickets, 

 " Male, Panama," and was acquired by the late Lord Derby in 1846. 

 Another example of this same bird, of which I have a note, is in the 

 splendid collection belonging to the Academy of Natural Sciences of 

 Philadelphia ; it is labelled ' Nicaragua.'' I took a description of 

 it in the autumn of 1856, but was loath to publish it without seeing 

 a second specimen. 



2. Dysithamnus olivaceus. 



Thamnophilus olivaceus, Tsch. Consp. Av. p. 278, et Faun. Per. 

 p. 174. 



Dysithamnus olivaceus, Cab. Orn. Not. i. 223 ; Bp. Consp. p. 199. 



$ . Olivaceus : pileo cinerascente, capitis lateribus concoloribus : 

 subtus pallide cinereus ; gutture venire medio et crisso albi- 

 cantibus : campterio albo : alarum tectricibus albo anguste 

 marginatis. 



Long, tota 5*0, alse 2*5, caudse 1*7. 



Hab. In Bolivia {Bridges). 



Mus. Derbiano. 



A distinct species of Dysithamnus nearly allied to D. mentalis, 

 but recognizable by the absence of the black ear-mark, and darker 

 colour of the sides below. The example in the Derby Museum 

 from which I take my characters, was obtained through Mr. Cuming 

 in 1846, and was doubtless among the Bolivian birds collected by 

 Mr. Bridges. 



I have to express my acknowledgments of the liberality of the 

 Trustees of the Derby Museum, in allowing me the use of these and 

 several other birds for examination. Without actual comparison of 

 specimens it is nearly hopeless to attempt to determine species of this 

 and other similarly-complicated groups. 



