DISAPPEARANCE
OF
MOSQUITOS.
469
W h e n travellers j u d g e o n l y by their o w n sensations they differ from each other r e s p e c t i n g t h e a b u n d a n c e o f t h e m o s q u i t o s as they d o r e s p e c t i n g t h e progressive increase or diminution o f t h e temperature. T h e state o f o u r o r g a n s , the m o t i o n o f the air, its degree o f humidity o r dryness, i t s electric intensity, a t h o u s a n d c i r c u m s t a n c e s c o n t r i b u t e at o n c e t o make us suffer m o r e o r less from t h e heat and the insects. M y fellow travellers w e r e u n a n i m o u s l y o f o p i n i o n that Esmeralda was m o r e t o r m e n t e d b y m o s q u i t o s than the banks of the Cassiquiare, and even more than the t w o missions of the G r e a t C a t a r a c t s ; whilst I , less sensible than t h e y of the high t e m p e r a t u r e o f the air, t h o u g h t that t h e irritation p r o d u c e d b y the insects w a s s o m e w h a t less at Esmeralda than at t h e entrance o f t h e U p p e r O r i n o c o . O n hearing the complaints that a r c made o f these t o r m e n t i n g insects i n hot countries it is difficult t o believe that their absence, o r rather their sudden disappearance, could b e c o m e a subject of i n q u i e t u d e ; y e t such is t h e fact. T h e inhabitants o f Esmeralda related t o u s , that i n the y e a r 1 7 9 5 , an hour before sunset, when the m o s q u i t o s usually form a very thick cloud, the air was observed t o b e suddenly free from t h e m , During t h e space o f t w e n t y m i n u t e s , n o t o n e insect was perceived, a l t h o u g h t h e s k y w a s cloudless, a n d no w i n d announced rain. I t is necessary t o have lived i n t h o s e countries t o c o m p r e h e n d t h e d e g r e e o f surprise which the sudden disappearance o f t h e insects must have p r o d u c e d . T h e inhabitants congratulated each other, and inquired whether this state of happiness, this relief from pain (felicidad y a l i v i o ) , c o u l d b e of any duration. But soon, instead o f e n j o y i n g the present, they yielded t o chimerical fears, and imagined that the order o f nature was perverted. S o m e old Indians, t h e sages o f the place, asserted that t h e disappearance o f the insects must b e t h e p r e c u r s o r o f a great earthquake. W a r m discussions a r o s e ; t h e least noise amid the foliage o f the trees was listened t o with an attentive e a r ; and when the air was again tilled with m o s q u i t o s they were almost hailed with pleasure. W e could not guess what modification o f the atmosphere had caused this phenomenon, which m u s t n o t b e c o n f o u n d e d with the periodical replacing of o n e species of insects b y another.