DISAPPEARANCE OF MOSQUITOS. 400 



When travellers judge only by their own sensations they 

 dilier from each other respecting the abundance of the 

 mosquitos as they do respecting the progressive inciease or 

 diminution of the temperature. The state of our organs, 

 the motion of the air, its degree of humidity or dryness, its 

 electric intensity, a thousand circumstances contribute afc 

 once to make us suffer more or less from the heat and tfae 

 insects. My fellow travellers were unanimously of opinion 

 that Esmeralda was more tormented by mosquitos than the 

 banks of the Cassiquiare, and even more than the two missions 

 of 'the Great Cataracts ; whilst I, less sensible than they of 

 the high temperature of the air, thought that the irritation 

 produced by the insects was somewhat less at Esmeralda 

 than at the entrance of the Upper Orinoco. On hearing 

 the complaints that are made of these tormenting insects in 

 hot countries it is difficult to believe that their absence, or 

 rather their sudden disappearance, could become a subject 

 of inquietude; yet such is the fact. The inhabitants of 

 Esmeralda related to us, that in the year 1795, an hour 

 before sunset, when the mosquitos usually form a very thick 

 cloud, the air was observed to be suddenly free from them. 

 During the space of twenty minutes, not one insect was 

 perceived, although the sky was cloudless, and no wind 

 announced rain. It is necessary to have lived in those 

 countries to comprehend the degree of surprise which the 

 sudden disappearance of the insects must have produced. 

 The inhabitants congratulated each other, and inquired 

 whether this state of happiness, this relief from pain (feli- 

 cidad y alivio), could be of any duration. But soon, instead 

 (( enjoying the present, they yielded to chimerical fears, 

 and imagined that the order of nature was perverted. Some 

 old Indians, the sages of the place, asserted that the disap- 

 pearance of the insects must be the precursor of a great 

 earthquake. Warm discussions arose ; the least noise amid 

 the foliage of the trees was listened to with an attentive 

 rar ; and when the air was again filled with mosquitos they 

 were almost hailed with pleasure. We could not guess 

 what modification of the atmosphere had caused this pheno- 

 menon, which must not be confounded with the periodical 

 replacing of one species of insects by another. 



