12 MOSQUITOES OF NORTH AMERICA 
suffer even more from mosquitos than at Carichana, but at Aturés, and above 
all at Maypurés, this suffering reaches its maximum. I doubt whether there is 
any part of the earth where man can be exposed to more cruel torments during 
the rainy season. In passing the fifth degree of latitude one is somewhat less 
bitten, but on the upper Orinoco the bites are more painful because of the heat 
and the absolute lack of wind. } 
“One should be in the moon,’ said a Saliva indian to Father Gumilla, ‘ for 
in its beautiful and clear light one would be free from mosquitoes.’ These 
words coming from a savage are very remarkable. Everywhere this satellite of 
the earth is for the American savage the habitation of happiness, the country of 
abundance. The Eskimo who counts among his riches a plank or tree trunk 
thrown by the waves upon a coast deprived of vegetation, sees in the moon 
plains covered with forests. The indians of the forests of the Orinoco see bare 
fields in which the inhabitants are never bitten by mosquitoes. 
“ Going further towards the South where the system of brownish yellow river 
waters begins, which are generally called black waters, upon the banks of the 
Atabapo, of the Temi, of the Tuamini, and of the Rio Negro, we enjoyed a repose, 
I had almost said an unexpected happiness. These rivers run through thick 
forests like the Orinoco, but the Nemocera and gnats, and the crocodiles as well, 
avoid the neighborhood of the black waters. Are these waters, a little colder and 
chemically different from the white, unsuitable for the larve and nymphs of 
the Nemocera which must be considered as true aquatic animals? Some small 
rivers, which are dark blue or yellowish brown, like the Toparo, the Mateveni, 
and the Zama, are exceptions to the general rule of the absence of mosquitos near 
black waters. These three rivers swarm with them, and even the indians discuss 
the problematical causes of this phenomenon. In descending the Rio Negro 
we breathed freely at Maroa, at Vavipe, and at San Carlos, villages situated on 
the borders of Brazil. But this amelioration of our condition was very short, for 
our sufferings recommenced when we entered the Cassiquiare. At Esmeralda, at 
the eastern extremity of the upper Orinoco, where the country known to the 
Spaniards ends, the clouds of mosquitos are almost as thick as in the Grand 
Cataracts. At Mandavaca we found an old missionary who told us with an air of 
sadness that he had passed his twenty years of mosquitos in America. He told 
us to look at his legs in order that we might be able to tell the people some day 
across the sea what the poor monks suffer in the forests of the Cassiquiare. As 
each bite leaves a little brownish black spot, his legs were so speckled that one 
could with difficulty see the whiteness of his skin between the spots of coagulated 
blood. While the insects of the genus Simulium abound on the Cassiquiare, 
which has white waters, the Culex or zancudos are proportionately rare; one 
hardly encounters them, whereas on the rivers which have black waters, on the 
eel and the Rio Negro, there are generally many zancudos and no mos- 
quitos.... 
“JT have just shown according to my own observations that the geographic 
distribution of venomous insects varies according to whether the water is white 
or black, and it is much to be desired that a learned entomologist should study 
upon the spot the specific differences between these criminal insects which play 
in the torrid zone, in spite of their minute size, a very important part in the 
economy of nature. What appears to us very remarkable, and it is a fact known 
to all the missionaries, is that the different species do not associate, and that at 
different hours of the day one is bitten by distinct species. Each time the scene 
changes, and when, according to the naive expression of the missionaries, other 
insects mount guard, one has some moments, even a quarter of an hour, of rest. 
The insects which disappear are not immediately replaced in the same number 
by those that succeed them. From half past six in the morning until five o’clock 
