368 CYPSELIDA. 
genus and sometimes in the other. Its position is best recognized under a distinct 
name and placed between the two above-mentioned genera. From Cypselus, Aéronautes 
may be distinguished by the toes as well as the tarsi being feathered and in having 
the outermost tail-feather on either side shorter than the next. Aéronautes agrees 
with Panyptila in having feathered toes, but the tail is much less deeply forked, the 
feathers wider, less acute at their ends, and the outermost pair shorter than the next. 
The outermost primary is shorter than the second and equal to the third, and is thus 
shorter as. well as blunter than the same feather of Panyptila. In nidification <Aéro- 
nautes agrees with Cypselus rather than with Panyptila. 
The range of Aéronautes as given in detail below extends from Wyoming Territory 
southwards through California to Arizona and Western Texas and to Mexico and 
Guatemala. 
1. Aeronautes melanoleucus. 
« Acanthylis saxatilis,? Woodh. Expl. Zuiii and Colorado Rivers, p. 64 (1853)*; Coues, Ibis, 
1865, p. 536 *. . 
Panyptila saxatilis, Coues, Birds N. W. p. 265°; Hensh. in Wheeler’s Surv., Zool. v. p. 870°. 
Cypselus melanoleucus, Baird, Pr. Ac. Phil. 1854, p. 118”. 
Panyptila melanoleuca, Baird, Birds N. Am. p. 141, t. 18. f. 1°; Scl. & Salv. Tbis, 1859, p. 125 7; 
Scl. P. Z. S. 1865, p. 607°; Sumichrast, Mem. Bost. Soc. N. H.i. p. 562°; Baird, Brew., 
& Ridgw. N.-Am. Birds, i1. p. 424". 
Micropus melanoleucus, Shufeldt, Ibis, 1887, p. 151, t. 5**. 
Aéronautes melanoleucus, Hartert, Cat. Birds Brit. Mus. xvi. p. 459 ™. 
Niger, fronte, cervice postica, et capitis lateribus magis fuliginosis; gutture toto, abdomine medio, plaga 
utringue hypochondriali, campterio alari, et secundariis ad apicem albis, plumis ad gutturis latera et 
pectoris fusco marginatis ; rectrice extima in pogonio externo stricte albo marginato, reliquis (duabus 
mediis exceptis) in pogonio interno plaga elongata alba ad basin notatis: rostro nigro, digitis cum 
unguibus suis flavidis. Long. tota circa 6-0, ale 5:9, caudex rectr. med. 1°8, rectr. lat. 2:3. 
© mari similis. (Descr. maris ex Duefias, Guatemala. Mus. nostr.) 
Hab. Norta America, Wyoming, California, Utah, New Mexico, Colorado, and 
Arizona? 4.—Mexico (Mus. Brit.1*), Mountains of Orizaba? (Sumichrast °) ; 
GUATEMALA, Gorge of Rio Guacalate near Duefias (0. S. & F. D. G.7). 
Dr. Woodhouse no doubt saw birds of this species at Inscription Rock in 1851, 
when he accompanied Sitgreaves’s Expedition to the Zufii and Colorado Rivers}. As 
he did not obtain specimens, his name for the species, ‘‘ Acanthylis saxatilis,” rests 
upon a somewhat questionable basis. Dr. Coues?%, and after him Mr. Henshaw‘ and 
others, have, however, used the name Panyptila saxatilis in preference to that of 
Cypselus melanoleucus given to it in 1854 by Baird from a specimen obtained by 
Kennerly and Mollhausen in the San Francisco Mountains®. Recent American 
writers have now reverted to melanoleucus, which was for many years the only specific 
name employed. 
