PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 467 



Dioctcs, Reichenb., Av. Syst. Nat. 1850, pi. 6G, fig. (type, D. 2}y''''^'ol(vma, Reichenb., 

 = Tyranmts caroUnensis ? ; no description!). 



SateUus, Reichenb., 1. c. (type, Tyranmis vodfcrans, Swains.?; no description). 



y Lnplujctcs, Reichenb., 1. c. — Cabax. & Heine, Mus. Heiu. II, 1859, 76 (includes T. 

 melanchoUcus, T. " satrajia", T. apoUtes, T. vociferans, and T. verticalis). 



^ McUttarchus, Caban., J. f. O., Nov. 1855,477 (type, Tyrannusmagniroatris, D'Orb. ; in- 

 cludes also T. crmi^iro'iiris and T. domwiceiisis). — Caban. & Heine, Mus. Hein. 

 II, 18.59, 80. 



Gen. Ch. — Tyraut-birds of large, medium, or ratlier small size, witli 

 strong-, conical -bills, strongly bristled rictus, even, emarginated, or 

 slightly rounded tail, and tlie ends of the outer primaries abrujitly nar- 

 rowed (except in T. luggeri). Crown with a concealed colored crest (red, 

 orange, or yellow) ; plumage without streaks or bars. 



The above brief diagnosis, although imperfect, will suffice to distin- 

 guish the members of Tyrannns from those of allied genera. Milvulus 

 agrees in the attenuation of the outer primaries, the colored crest, and 

 many other features, but the tail is excessively forked, the lateral 

 feathers twice or more as long as the njiddle pair. Pltangus is also quite 

 similar in many respects, but has the bill more elongated, less depressed, 

 the outlines straighter, while there are various other differences. Upon 

 tlie whole, the genus may be considered quite a natural grou}). 



The species vary among themselves not onlj' in colors, but in other 

 respects also, each one (with a single exception so fiir as I know*) hav- 

 ing its own peculiarities of external form, so that were all identical in 

 coloration they could even then be readily distinguished. Attempts 

 have been made to subdivide the genus, but all have proved unsatisfac- 

 tory. There is, trulj', a vast difference in size and form between the ro- 

 bust, almost gigantic, T. magnirostris, and the little T. mirantio-atrocris- 

 tatns ; but other species are variously intermediate, so that it seems best 

 to consider the variations of form and size in this genus as of mere spe- 

 cihc importance. 



Conspcchin Tyrutnionini. 



A. White beueatl), the chest shaded with pale grayish (very faint in T. magnirostris). 

 a. Tail distinctly emarginate at end. Bill very large, much longer than tarsus (measur- 

 ing front, nostril to tip). Tail not sharply tipped ivith white (^ Melitlarchus, 

 Cabanis, part). 



1. Wing, .5.20-5.30; tail, 4.00-4.25; bill, from nostril, 1.00-1.05, its depth at 



base .42-. 4G, width .GO-. 64 ; tarsus, .88; middle toe, .72. Grayish brown 

 above, the head l)lackish snuff-brown. Hah. — Cuba : Bahamas. 



T. MAGNIROSTRIS. 



2. Wing, 4.70-4.75; tail, 3.85-4.20; bill, from nostril, .92-.95, its depth 



.34-40, width .58-.60; tarsus, .70; middle toe, .58-.62. Plumbeous-gray 

 above, the head similnr. TIah. — Guiana, Trinidad, Isth. Panama (?), and 

 Lesser Antilles T. rostratus. 



3. Wing, 4.4.5-4.80 ; tail, 3.50-4.05; bill, from nostril, .75-.82, depth .30-.36, 



width .47-..55 ; tarsus, .70-.75 ; middle toe, .52-.60. Colors of rostratus, 

 but somewhat lighter plumbeous above. ITah. — West Indies and adja- 

 cent coasts T. DOMINICENSIS. 



*T. rostratus and T. dominicensis are alike in the details of structure. 



