216 The Naturalist in La Plata. 



Gould tried to obtain others, offering as much as 

 fifty pounds for one ; but no second specimen ever 

 gladdened his eyes, nor was anything more heard 

 of it until Stolzmann refound it in the year 1880. 



The addition of many new species to the long 

 list would, however, be a matter of small interest, 

 unless fresh facts concerning their habits and 

 structure were at the same time brought to light ; 

 but we can scarcely expect that the as yet un- 

 known species will supply any link connecting the 

 Trochilidas with other existing families of birds. 

 The eventual conclusion will perhaps be that this 

 family has come down independently from an 

 exceedingly remote past, and with scarcely any 

 modification. While within certain very narrow 

 limits humming-birds vary more than other families, 

 outside of these limits they appear relatively 

 stationary; and, conversely, other birds exhibit 

 least variability in the one direction in which 

 humming-birds vary excessively. On account of a 

 trivial difference in habit they have sometimes been 

 separated in two sub-families : the Phaethornithinse, 

 found in shady tropical forests ; and the Trochilinae, 

 comprising humming-birds which inhabit open sunny 

 places and to this division they mostly belong. In 

 both of these purely arbitrary groups, however, the 

 aerial habits and manner of feeding poised in the 

 air are identical, although the birds living in 

 shady forests, where flowers are scarce, obtain 

 their food principally from the under surfaces of 

 leaves. In their procreant habits the uniformity is 

 also very great. In all cases the nest is small, deep, 

 cup-shaped, or conical, composed of soft felted mate- 



