[1889. BOTANICAL GAZETTE. 



251 



was resting upon something besides dead wood. It was 

 the home of a colony of what is called " soldier ants," an 

 insect nearly half an inch long and with a round black head 

 which seems to be one-third the size of its body, and armed 

 with formidable forceps. In a spirit of spitefulness, I took 

 a stick and broke their nest to pieces, and so fierce were the 

 creatures that they attacked my stick viciously, and doubt- 

 less would have bitten me to death could they have reached 

 me. Plants which are defended by such ants and also b\ 

 large red wasps, hornets and spiders, which make their home 

 upon them, are not to be touched with impunity. A wasp 

 whose bower I had entered in search of specimens, stung 



me so severely that I was glad to retreat with the most un- 

 ceremonious haste. 



Other plants are guarded against mutilation in a different, 

 but perhaps none the less effective, manner. They pour out 

 a copious discharge of acid, milky juice, which sometimes 

 u raises a blister upon the skin, and is always unpleasant to 

 encounter. An Asclepiad growing near Asuncion, from 

 wheh I cut branches, discharged such large drops of viscid 

 milk upon my hands and clothing that I wished I had let it 

 alone, and the specimens adhered to the leaves of the port- 

 folio and the sheets of drying paper as though they had been 

 smeared with postage-stamp mucilage. On another occasion, 

 while making my way through a dense wood, I heard a pat- 

 tering like the "falling of rain-drops. As it was a bright, 

 sunshiny day, I was curious to learn the cause of the sound. 

 Upon investigation, I found that it was occasioned by drops 

 of milk, which were falling in a shower from the leaves of a 

 large tree. The ground was quite white with the drops. 

 Many cattle were grazing in the vicinity, but I noticed that 

 they scrupulously avoided this tree, and never browsed upon 

 its leaves, although they ate almost everything else within 

 reach. 



The greatest obstacle to the preservation of botanical spe- 

 cimens lies in the excessive humidity of the climate. The 

 atmosphere seems to be loaded with vapor at all times, even 

 m the most cloudless weather. The average annual rainfall 

 it Asuncion, and probablv that of Paraguay in general, is 

 about 70 inches. Some scientists estimate it as high as 80 

 inches. 2 This year, according to meteorological statistics 

 kept by government, the rainfall has been a little more than 

 7o inches. With such an amount of humidity in the air, of 



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