156 UP THE RIVER OF TAPIRS [chap, v 



At this point both Cherrie and Miller collected a 

 number of mammals and birds which they had not 

 previously obtained ; whether any were new to science 

 could only be determined after the specimens reached 

 the American museum. While making the round of 

 his small mammal traps one morning, MiUer encountered 

 an army of the formidable foraging-ants. The species 

 was a large black one, moving with a well-extended 

 front. These ants, sometimes called army-ants, like the 

 driver-ants of Africa, move in big bodies and destroy or 

 make prey of every living thing that is unable or un- 

 willing to get out of their path in time. They run fast, 

 and everything runs away from their advance. Insects 

 form their chief prey ; and the most dangerous and 

 aggressive lower-hfe creatures make astonishingly httle 

 resistance to them. Miller's attention was first attracted 

 to this army of ants by noticing a big centipede, nine or 

 ten inches long, trying to flee before them. A number 

 of ants were biting it, and it writhed at each bite, but 

 did not try to use its long curved jaws against its 

 assailants. On other occasions he saw big scorpions 

 and big hairy spiders trying to escape in the same way, 

 and showing the same helpless inability to injure their 

 ravenous foes, or to defend themselves. The ants climb 

 trees to a great height, much higher than most birds' 

 nests, and at once kiU and tear to pieces any fledghngs 

 in the nests they reach. But they are not as common as 

 some writers seem to imagine ; days may elapse before 

 their armies are encountered, and doubtless most nests 

 are never visited or threatened by them. In some 

 instances it seems likely that the birds save themselves 

 and their young in other ways. Some nests are in- 

 accessible. From others it is probable that the parents 

 remove the young. MiUer once, in Guiana, had been 



