INSECT PESTS 217 



dead, or standing motionless waiting for death. From 

 time to time we had to leave behind one of our own 

 mules. 



It was not always easy to recognize what pasturage 

 the mules would accept as good. One afternoon we 

 pitched camp by a tiny rivulet, in the midst of the 

 scrubby upland forest ; a camp, by the way, where the 

 piums, the small, biting flies, were a torment during 

 the hours of daylight, while after dark their places were 

 more than taken by the diminutive gnats which the 

 Brazilians expressively term " polvora," or powder, and 

 which get through the smallest meshes of a mosquito- 

 net. The feed was so scanty, and the cover so dense, 

 at this spot that I thought we would have great difficulty 

 in gathering the mules next morning. But we did not. 

 A few hours later, in the afternoon, we camped by 

 a beautiful open meadow ; on one side ran a rapid 

 brook, with a waterfall 8 feet high, under which we 

 bathed and swam. Here the feed looked so good that 

 we all expressed pleasure. But the mules did not like 

 it, and after nightfall they harked back on the trail, and 

 it was a long and arduous work to gather them next 

 morning. 



I have touched above on the insect pests. Men 

 unused to the South American wilderness speak with 

 awe of the danger therein from jaguars, crocodiles, and 

 poisonous snakes. In reality, the danger from these 

 sources is trivial, much less than the danger of being 

 run down by an automobile at home. But at times the 

 torment of insect plagues can hardly be exaggerated. 

 There are many different species of mosquitoes, some of 

 them bearers of disease. There are many different kinds 

 of small, biting flies and gnats, loosely grouped together 

 under various titles. The ones more especially called 



