6l6 RUBBER 



keep a clear area of bare soil (swept clean of all rubbish) 

 around each tree. There are various substances that may 

 be spread on the ground to act as a deterrent against the 

 passage of the slugs, such as lime and soot. But these 

 soon lose their efficacy in rainy weather, which is exactly 

 the time when the slugs are most active. They depend, 

 for their efficient action, upon their caustic and desiccating 

 properties respectively, both of which are lost after 

 exposure to rain. Moreover, these slugs have the power 

 of secreting copious quantities of mucus, from a special 

 slime gland at the extremity of the body, which assists 

 them to rid themselves of the obnoxious substance. 

 Cinders, owing to their prickly surface, are a more 

 efficient protection. Although the slug is provided with 

 eyes, these organs are of a rather rudimentary character, 

 and can be of little or no assistance to the animal in its 

 search for food. Scent is almost certainly the guiding 

 sense. Consequently, a protective barrier of some 

 strongly smelling substance is more likely to turn them 

 aside from their objective. A very effective deterrent 

 can be made by damping sawdust with crude carbolic acid 

 or phenyl. Either of these substances may be spread 

 on the ground round the base of the tree to be protected. 

 Another plan is to tie cylinders of freshly tarred paper 

 round the stem of each tree. The paper should be tarred 

 on the outside only, and its lower edge should be covered 

 up with earth to prevent the slugs from creeping beneath 

 the paper. Professor Newstead, in his report on the 

 West Indian slug of similar habits, recommends girdling 

 the trees with cotton-wool. This may be effective while 

 the wool remains fresh, but the first tropical shower 

 would reduce it to a pulpy mass that would present no 

 difficulty to the ascent of the slugs. A more effective 

 girdle may be contrived with rough coconut fibre steeped 

 in coal tar. 



INSECTS. 



We now come to the class Insecta, which furnishes by 

 far the greater number of the pests with which we have 

 to deal. The several orders will be taken separately. 



