536 NATURAL SCIENCE. se^I- 



is so severe a check to its growth, that even if it should overcome one 

 such calamity, it is weakened for a long time afterwards. 



Imported fruit trees, and especially palms, are much infested by 

 scale insects. These cover the under surface of the leaves and suck 

 the juices, causing sickness, and even death. Often they are accom- 

 panied by fungoid growths, which hasten the end. The mango is 

 much infested by both scale insects and fungus, and may live in this 

 condition for many years. The under surfaces become spangled with 

 a pretty star-like scale, and as this carries on its work of depletion, 

 the foliage begins to look dirty and unhealthy, while in its later 

 stages the fungus flakes off. At first the tree loses its power of 

 ripening fruit, then no flowers are produced, and finally it may linger 

 for years a centre of infection to others, until the owner chops it 

 down as an unsightly pest. It does its best to get rid of its parasite 

 by dropping leaf after leaf, and developing new ones, but both scale 

 and fungus multiply and attack them almost as soon as they unfold. 



Unlike some other countries, Guiana has few herbivorous 

 animals. Tapirs and manatees do not interfere with the forest trees, 

 and even the rodents confine themselves to fruits or water plants. 

 The young seedlings are never bitten off, nor is the bark gnawed. 

 It follows, therefore, that protective measures against the larger 

 animals are unnecessary, and every effort can be used for other 

 purposes. Unhampered by outsiders, the plants only contend among 

 themselves, thus contrasting with European vegetation, where 

 thousands of signs indicate a struggle with outside enemies which 

 in the tropical forest are almost entirely wanting. 



James Rodway. 



