Listen to Adrian Cowell:
For the next few days we advanced at a steady mile and a quarter a day. But we were moving into a deeper valley, and soon progress became slow and trying. There were so many biting flies that a hundred marks could be counted on every hand; and in the evenings, if you tried to pull away the crab-like ticks, the flies pounced on every exposed inch of skin. The mosquitoes hunted in clouds, a foot-insect laid it eggs beneath our toe-nails, and the horse-flies had such long bloodsuckers that just when you taught that you were protected by three layers of hammock, blanket and jeans, they would stab you neatly in the behind.
At the cutting-head, Pripuri had to be careful of the hornet's nests which hung in the bushes. We ran when we heard his shout, and once, when I was stung four times on the lips, I was delirious for most of the night. In one camp, about fifty ants scrambled on to our shoes and up our legs at every step, and in another, the whole ground seemed to be black and moving. One Indian was stung by a scorpion, and several Kayabi were bitten by the inch-long "formigao" ant, whose bite can bring a fewer.
But is was the sweat bees that won the title of plague of plagues. As soon as we stopped moving they swarmed up our nostrils, down our ear-lobes, under our eye-lids, crawling over every centimetre of our body, sucking for salt. Someone had once told me about the 'Geneva convention' of the jungle; if the flies bite by day, then the mosquitoes fold their wings at night. But in the soggy forest between two ranges of hills we were breakfast, lunch and dinner for everything that was hungry, and there was one novelty which not even Claudio [Villas-Boas] had met before,. Hard marble-sized boils appeared on exposed areas of skin, obviously caused by bites; but though we watched, we never discovered who did the biting.