222 
Flowers and Insects. 
[April, 
Guayana an exceedingly rich flora, with but a very scanty 
fauna as far as insedls are concerned. This assertion needs 
further examination. Waterton had previously visited the 
same regions, but he has unfortunately left nothing on 
record which might throw any diredl light upon the question, 
though he states in the “ Wanderings ” that “ almost every 
flower of tropical climates contains insedls of one kind or 
other,” and generally speaking the mountainous parts of the 
Neotropical region are by no means poor in insedls adapted 
for visiting flowers. 
It may be asked to what cause does M. Heckel himself 
ascribe the brilliance and purity of the Alpine flora ? He 
seeks their origin in “ the solar radiations, which are more 
intense than in plains.” 
Before at all accepting this explanation we must pause 
and ask whether the brilliant colouration of the organisms in 
any country bears a fixed relation to the clearness of its 
skies and the intensity of its illumination ? There is — to 
put the case in the most cautious and moderate manner' — 
no evidence to this effedl. The brilliant skies of Persia, 
Arabia, and the Sahara, free as they are from fog and cloud, 
have not fostered a brilliant flora and fauna. On the con- 
trary, in those regions everything seems to tend towards 
what may well be called “ desert-colour.” On the other 
hand, the Cape of Good Hope has — or rather had, for the 
goats have destroyed it — a far more brilliant flora. 
There is another fadl to be considered and accounted for : 
what of the Alpine fauna ? If the intensity of the solar 
radiations produces brilliant colouration in plants, should it 
not have a similar effedl upon insedls ? Yet this is precisely 
what is not recognised. M. Heller remarks that, with the 
exception of the Chrysomelidae, most Alpine insedls are 
black or deep brown, and the higher we ascend the more 
sombre grow <their colours. In other animals a similar 
tendency to melanism prevails. The fish in Alpine lakes 
have chiefly dark colours. Similarly among reptiles we find 
the jet-black Salamandra atra taking the place of the orange- 
blotched S. maculata of the plains. The common viper 
takes in high mountains an almost black colouration, and 
was formerly looked upon as a distindt “ good species,” 
under the name Berus prester. 
But whilst the dark and dull charadter of the Alpine 
fauna militates decidedly against the above-mentioned hypo- 
thesis of M. Heckel, it is equally little in favour of the 
well-known views of Mr. Grant Allen. This able observer 
suggests that brilliance and purity of colour in the animal 
