SOURCE or TUE STING. 
2S7 
Bataillez, in tlie road from Carthagena to Honda, while wo 
were dissecting a crocodile eleven feet long, the smell of 
which infested all the surrounding atmosphere. The Indians 
much commend the fumes of burnt cow-dung. When the 
wind is very strong, and accompanied by rain, the mosquitos 
disappear for some time: they sting most cruelly at the 
approach of a storm, particularly when the electric explo- 
sions are not followed by heavy showers. 
Anything waved about the head and the hands contri- 
Elites to chase away the insects. “ The more you stir your- 
^elf, the less you will be stung,” say the missionaries. ’ The 
zancudo makes a buzzing before 'it settles ; but, when it 
Iaa assumed confidence, when it has once begun to fix its 
sucker, and distend itself, you may touch its wings without 
ds being frightened. It remains the whole time with its 
two hind legs raised; and, if left to suck to satiety, no 
swelling takes place, and no pain is left behind. We often 
fepeated this experiment on ourselves in the valley of the 
-Kio Magdalena. It may be asked whether the insect 
deposits the stimulating liquid only at the moment of its 
mght, when it is driven away, or whether it draw's the 
bquid up again when left to suck undisturbed. I incline to 
‘da latter opinion ; for on quietly presenting the back of 
ln y band to the Culex cyanopterus, I observed that the 
Pain, though violent in the beginning, diminishes in pro- 
portion as the insect continues to suck, and ceases altogether 
When it voluntarily flies away. I also wounded my skin 
" ‘th a pin, and rubbed the pricks with bruised mosquitos, 
:, pd no swelling ensued. The irritating liquid, in which 
demists have not yet recognized any acid properties, is 
yontained, as in the ant and other hymenopterous insects, 
111 particular glands ; and is probably too much diluted, aud 
consequently too much weakened, ‘if the skin be rubbed 
" Ah the whole of the bruised insect. 
i have thrown together at the dose of this chapter all 
f .learned during the course of our travels on phenomena 
uch naturalists have hitherto singularly neglected, though 
j. ah exercise a great influence on the welfare of the inha- 
1 aQ ts, the salubrity of the climate, and the establishment 
»ew colonies on the rivers of equinoctial America. I 
l gnt justly have incurred the charge of having treated 
