62 PROCEEDINGS OF THE ACADEMY OF 



extent and even in pattern in the same individual at different 

 stages of plumage, that we can only compare age for age and 

 season for season with any success in determination of specific 

 characters. It is most probable that even the wide limits I set for 

 variability in this respect, due to age, season, and individual pecu- 

 liarity, will require to be somewhat enlarged. 



The foregoing paragraphs must not be construed as any attempt 

 to undervalue the interesting and sometimes extremely curious 

 characters distinguishing the several species. Though in the 

 following pages I may appear to have "unnecessarily," if not 

 unwarrantably, reduced the number of species, }^et I am persuaded 

 that no unprejudiced ornithologist could have reached different 

 conclusions upon study of the same material. It may be well to 

 remember that two hundred specimens of Myiarchus have never 

 before been examined by one person at a coup d'ceil; and I really 

 think that with two thousand specimens instead of two hundred, 

 I should not be able to establish as many species as are here 

 allowed. Others will judge whether I have placed the species 

 here discussed upon sure footing ; I simply ask for impartial 

 criticism. 



1. Myiarchus validus. 



Tyrannus crinitus, Gosse, B. Jam. 18G ; nee anct. 

 Myiarclius validus, Cab., Orn. Not. ii. 351, et auct. 

 Myionax validus, Cab., M. H. ii. 73. 

 Pyroceplialus {Myionax) validus, Gr., H.-L. No. 5520. 

 Tyrannula gossii, Bp., C. A. i. 189. 

 Bed Petchary, Anglice. 



M. inter majores, rostro crasso, tarsum requante ; coloribus 

 intensis ; olivaceo-fuscus, gula cinereo-plumbea, hinc ventre sensim 

 sordide flavido ; remigibus, rectricibus tectricibusque alarum supe- 

 rioribus et intus et extus rufomarginatis, tectricibus alarum cau- 

 daeque inferioribus rufescentibus. Long. tot. t. 50-8.50, alas et 

 caudre 3.80-4.20, tarsi et rostri .80-.90, digiti 3tii cum ungue 

 .70-.80; rostri latitudo ad nares .35-.40. (Poll. Angl. et dec.) 



Hab. Ins. Jamaica. (Mus. S. I. et Gr. N. L.) 



Obs. A stationary localized form which by isolation from its 

 allies and continuous subjection to special modifying influences, 

 has become so far differentiated as to be recognizable on sight, 

 and which is not now known to intergrade with its nearest ally, 

 crinitus. 



[July 2, 



