Zoological Explorations. 271 



Order MACRO C HIRES. Goatsuckers, Swifts, etc. 

 Family caprimulgid.e. Goatsuckers. 



Chordeiles virginiaxus hexryi (Cass.). Wesfo'u jVight- 

 Hazvk. Exceedingly abundant on pleasant evenings near our 

 camp at Grand Rapids. The specimens secured are referred 

 with some doubt to this species. They average much grayer 

 on the upper surface, especially on upper wing-coverts, than 

 C. z'irginianiis, but we have one specimen of the latter from 

 Iowa that is as gray as any collected on the Saskatchewan. 

 The pattern of the mottling is much finer in the northern 

 specimens, and the white at bend of wing considerably less 

 conspicuous. 



Eight specimens secured : 3 c, 4 2, i (?) 



Order PASSERES. Perching Birds. 

 Family tyraxnid.e. Tyr.\xt Flycathers. 



Tyraxxus Tyraxxus (Linn.). King-bird. Common at 

 Grand Rapids and Chemawawin. This is the only species 

 that we found that has a concealed crest. That this crest in 

 the flycatchers is useful as a decoy to insects has been demon- 

 strated by the observations of Beckham and of the writer, ^ 

 and yet a recent study of all the specimens of the family at 

 the Smithnonian has failed to establish any generalization that 

 will throw light upon the distribution of this concealed crest 

 among the Tyrannidse. Judging from the North American 

 forms, I was led to think that the size of the birds had some- 

 thing to do with the matter, but some of the smallest Central 

 American genera, e. g. tyra}2nulus^ have the crest, while some 

 of the largest are without it. It was thought, also, that it 

 was a constant generic character, but this also fails as a 

 theory, because several genera have some species with and 

 some without the crests. It thus appears that these interest- 

 ing structures are merely specific in character, and sometimes 

 not even that, e. g. Mihulus forjicatus. 



1 Proceedings U. S. National Museum Vol. V, p. 396. 



