12 MOSQUITOES OF NORTH AMERICA 



suffer even more from mosquitos than at Carichana, but at Atures, and above 

 all at Maypures, this suffering reaches its maximum. I doubt whether there is 

 any part of the earth where man can be exposed to more cruel tonnents 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 larvae 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 Simiilium abound on the Cassiquiare, 

 which has wliite waters, the Culex or zancudos are proportionately rare; one 

 hardly encounters them, whereas on the rivers which have black waters, on the 

 Atabapo and the Rio Negro, there are generally many zancudos and no mos- 

 quitos. . . . 



" I 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 



