84 WHAT MR. DARWIN SAW. 



BRAZIL. 



piece of ground. A little way behind, every stalk and leaf 

 was blackened by a small ant. The swarm having crossed 

 the bare space, divided itself and descended an old wall. 

 By this means many insects were fairly enclosed ; and the 

 efforts which the poor little creatures made to extricate 

 themselves from such a death were wonderful. When the 

 ants came to the road they changed their course, and in 

 narrow files reascended the wall. When I placed a small 

 stone so as to intercept one of the lines, the whole body at- 

 tacked it, and then immediately retired. Shortly afterward 

 another body came to the charge, and again having failed 

 to make any impression, this line of march was entirely 

 given up. By going an inch round the file might have 

 avoided the stone, and this doubtless would have happened 

 if it had been there in the beginning ; but having been at- 

 tacked, the lion-hearted little warriors scorned the idea of 

 yielding. 



THE WASP. 



I WAS much interested one day by watching, in the neigh- 

 borhood of Rio, a deadly contest between a Pepsis and a 

 large spider of the genus Lycosa. The wasp made a sud- 

 den dash at its prey, and then flew away : the spider was 

 evidently wounded, for, trying to escape, it rolled down a 

 little slope, but had still strength enough to crawl into a 

 thick tuft of grass. The wasp soon returned, and seemed 

 surprised at not finding its victim at once. It then com- 

 menced as regular a hunt as ever hound did after fox; mak- 



