SIETSTES.— MTI0DTNA8TES. 47 



1. Sirystes albogriseus. (Tab. XXXVII. fig. l.) 



Lipangus albogriseus, Lawr. Ann. Lye. N. Y. viii. p. 9'. 



Sirystes albogriseus, Scl. & Salv. P. Z. S. 1880, p. 156 = ; Scl. Oat. Birds Brit. Mus. xiv. p. 182'. 



Supra cmereus ; uropygio albo ; capite summo nigro ; loris fuliginosis ; alls nigris, secundariis et tectricibus 

 late albo marginatis ; oauda nigra, stricte albo terminata : subtus albus ; gutture et hypochondriis cinereo 

 tinotis: rostro corneo, mandibula ad basin albieante; pedibus nigricantibus. Long, tota 7-3, alse 4-1, 

 caudse 3-5, tarsi 0-8, rostri a rictu 0-9. (Descr. exempl. ex Panama. Mus. nostr.) 



Hah. Panama, Veraguas {Arce 2), Lion Hill {M'Leannan i). 



Very little is known of this species, the first specimen of which was sent by 

 M'Leannan to Mr. Lawrence, who described it under the, name of Lipanyus albo- 

 griseus^. We have since received two specimens from the State of Panama, but we 

 are not informed of the exact spot where they were obtained. The species most nearly 

 allied to the one under consideration is S. alhocinereus of the valley of the Upper 

 Amazons. This differs in having the wing-coverts much more narrowly edged with 

 greyish white. 



MYIODYNASTES. 



Myiodynastes, Bonaparte, Compt. Rend, xxxviii. p. 637; Notes Orn. p. 87 (1856) ; Sol. Cat. Birds 



Brit. Mus. xiv. p. 182 (type Muscicapa audax, Gm.). 

 Hypermitres, Cabanis, J. f. Orn. 1861, p. 247 (type Scaphorhynchus chrysocephalus, Tsch.). 



This genus is divisible into two well-marked sections — one characterized by the breast 

 and flanks being conspicuously marked by black guttate spots, in the other the under 

 surface is uniformly coloured. 



In our region we find two of the former section, viz. M. luteimntris and M. audax, 

 nearly universally distributed, and one of the second, M. hemichrysus, restricted to Costa 

 ilica and the adjacent parts of the State of Panama. 



Of the first section we find it impossible to recognize more than three species, though 

 this view differs from that of several authorities on the subject. Thus Mr. Ridgway in 

 his 'Manual of North-American Birds' (p. 332), omitting all mention of if. solitarius, 

 recognizes two species, M. luteiventris and M. audax ; but divides the latter into three 

 races, M. audax proper, M. a. noUlis, and M. a. insolens. We, so far as the number 

 of species are concerned, confirm Mr. Ridgway' s views, but we fail to discriminate his 

 subspecies of if. audax. Mr. Sclater in his recent revision of the Tyrannidse divides this 

 section of the genus into four species, namely M. luteiventris, M. nobilis, if audax, 

 and M. solitarius. We now merge M. nobilis and M. audax under the latter name, 

 and somewhat alter the range defined of all the species, except M. solitarius. 



The question of distribution of these Myiodynastes is very singular, for with few 

 exceptions wherever if luteiventris is found M. audax occurs with it, and moreover 

 if. solitarius overlaps the range of if audax in many places. In spite of this con- 

 current range each form keeps its characters with great precision. 



