364 The Naturalist in La Plata. 
have some doubts; he might think that the 
stranger had, after all, only mocked him with the 
sight of a wonderful artificial gem, and that a close 
examination would have proved its worthlessness ; 
but the naturalist can have no doubts: if he is an 
enthusiast, well acquainted with the fauna of his 
district, and has good eyesight, he knows that there 
is no mistake; for there it is, the new strange 
form, photographed by instantaneous process on his 
mind, and there it will remain, a tantalizing image, 
its sharp lines and fresh colouring unblurred by 
time. 
Walking in some open forest glade, he may look 
up just in time to see a great strange butterfly—a 
blue Morpho, let us say, wandering in some far 
country where this angel insect is unknown—pass- 
ing athwart his vision with careless, buoyant flight, 
the most sylph-like thing in nature, and all blue 
and pure like its aérial home, but with a more 
delicate and wonderful brilliance in its cerulean 
colour, giving such unimaginable glory to its broad 
airy wings; and then, almost before his soul has 
had time to feel its joy, it may soar away unloitering 
over the tall trees, to be seen no more. 
But the admiration, the delight, and the desire 
are equally great, and the loss just as keenly felt, 
whether the strange species seen happens to be one 
surpassingly beautiful or not. Its newness is to the 
naturalist its greatest attraction. How beautiful 
beyond all others seems a certain small unnamed 
brown bird to my mind! So many years have 
passed and its image has not yet grown dim; yet I 
saw it only for a few moments, when it hopped out 
