270 NOTES OF A BOTANIST 
tolda, and this I could do undisturbed by the 
insects which are the greatest torment to the 
traveller on the Amazon. This is the great advan- 
tage of voyaging on black waters, that no carapana 
(or zaneudo, as the Spaniards call them) interrupts 
one's repose. I was often reminded too of what 
Humboldt says in his Aspects of Nature (vol. i. 
p. 215) respecting the wonderful clearness with 
which the constellations are reflected in black 
waters. I have nowhere seen with such mar- 
vellous distinctness what might seem the "skies 
of a far nether world " as when anchored by night 
in a still bay of the Rio Negro, and looking down- 
wards on its unruffled waters ; but when moving 
along every stroke of the oars dashes fifty stars to 
shivers and thus dispels the agreeable illusion. 
On the Upper Rio Negro there is no lack of insect 
plague by day, in the shape of two very minute flies, 
called pi'um and marui'm (the real mosquitoes " of 
the Spaniards), whose bites are most annoying and 
cause considerable swelling and irritation. They 
are found wherever the river inundates granite 
rocks (as at Sao Gabriel), and especially about the 
mouths of some affluents of the Rio Negro which 
have whitish water. The following extract is from 
my Journal of December 12, written ofl" Sta. 
Isabel: "Yesterday and to-day much tormented 
by marui'm. My hands, neck, and feet are painted 
with their bites. Whilst I write there is a cloud of 
them between my eyes and the paper, and several 
are feasting on my hands and face." To be ex- 
posed to such as this is no bagatelle, but I mind it 
little when I can look forward with tolerable cer- 
tainty to a quiet night's rest. I have conversed 
