NATURAL SCIENCES OF PHILADELPHIA. 57 



Genus MYIARCHUS Cabanis. 



Myiarclbus, Cab., Fn. Peruv. 1844, 152. Type Muscicapa ferox, Gm. 



Despoiina, Kaup, ? ,1851.' Type ? 



Kaupornis, Bp., ? Ateneo Italiauo, 1854. Type Myiobus stolidus, Gosse. 

 Blacicus, Cab., J. f. O. 1855, 480. Type Myiobius tristis, Gosse. 

 Myionaz, Cab., Mus. Hein. ii. 1859, 73. Type Muscicapa crinita, L. 

 Non Myiarchus apud Bp. Cousp. Av. i. 188. 

 Muscicapa, Tyrannus, Tyrannula, Aliquorum. 



The genus, so called, rests upon no structural characters, while 

 its synonyms are among the vagaries of ornithology. But the 

 term is a convenient designation of a group of flycatchers modelled 

 in the likeness of Musciaioa crinita, L. They stand near Tyr- 

 annus proper, and closely resemble the olivaceous, yellow-bellied 

 species ("Laphyetes") of the latter, such as verticalis ; but are 

 distinguished by not having the outer primaries emarginate, nor 

 the wings longer than the tail, nor a flame-colored crest. The bill 

 and feet of the two genera do not differ noticeably ; or rather, 

 these members, in the species of Myiarchus, waxy as much inter se 

 as the difference between 3Iyiarchus and Tyrannus in the same 

 respects. 



But the distinction between Myiarchus and Tyrannus, due to 

 the tolerably strong features of the latter genus, is considerable, 

 compared with the differences subsisting between 3Iyiarchus and 

 several allied olivaceous ltycatchers. Color aside, there are no 

 substantial characters by which the Myiarchi can be distinguished 

 generically from " Empidias" fuscus, "Empidonax" acadicus, 

 " My i odyfcastes" audax, and others, among which lam not sure 

 that some forms with which I am at present unacquainted may 

 not fall in Myiarchus as defined for the purposes of this paper. 



In the matter of external anatomy, or contour, we can only say 

 that Myiarchi are rather large tyrannulas, with the nearly even 

 tail so lengthened that when measured inside the coccyx, it equals 

 or rather exceeds the wing in length; with the wing rather short, 

 and its point formed by the third, or third and fourth quills, 

 closely supported by the second and fifth, the first being only as 

 long as the inner primaries; with the bill of the most ordinary 

 tyrannuline shape, a little more or less than half its own length 



1 I quote this and the following name on Gray's authority, haying no 

 means of verifying the references. 

 1872.] 5 



