92 BIOLOGICAL SOCIETY OF WASHINGTON. 



ment in Costa Rica, but extends northward to Guatemala, whence 

 northward it gradually passes into M. lawrencei. I have not seen 

 Arizona examples, but would have no hesitation in referring them 

 to olivascens on geographical grounds alone. That I am correct in 

 doing so is strongly indicated by the following quotation from Mr. 

 Brewster's remarks upon nine specimens obtained in the Santa Rita 

 Mountains, in southern Arizona, by Mr. F. Stephens. {Cf. Bull. 

 Nutt. Orn. Club, vii, Oct., 1882, p. 205): "These show little 

 variation in color or markings, but the females are slightly smaller 

 than the males. The characters which separate M. lawrencii from 

 its respective allies, M. trisfis, of Jamaica, and M. nigricapillus, of 

 Central America, are well maintained in this series." [67". Hist. 

 N. Am. B., ii, p. 333.] 



In this connection it may be well to give a brief review of the 

 Mexican Myiarchi, from the writer's standpoint, a special study of 

 the subject, based upon the extensive series in the National Mu 

 seum collection, (including many types,) enabling him to feel 

 pretty sure as to the limits of the respective species. 



In the National Museum we have the following : 



1. M. crinitus (LiNN.) CAB., as a migrant through eastern 

 Mexico. 



2. M. mexicanus (K.AUP) LAWR.: a. mexicanus, from eastern 

 Mexico, north to the lower Rio Grande Valley, in Texas ; b. mag- 

 ister, NOBIS, from western and southwestern Mexico, and north to 

 southern Arizona. 



3. M. nuttingi RIDGW. , from southwestern Mexico. (Cf. Proc. 

 U. S. Nat. Mus., vol. 5, pp. 394, 395-) 



4. M. yucatanensis LAWR. from Merida, Yucatan. (This seems 

 to me to be most nearly related to the Antillean species (M. 

 stolidus, etc). I have carefully examined the type, which is in 

 the National Museum collection, and cannot at all agree to its 

 reference to M. mexicanus.'} 



5. M. lawrencei (GiRAUD) BAIRD : a. lawrencei, from eastern 



