CHAP. XI. | THE CONTROL OF INSECT PESTS OF I ROPS. 



121 



In Rail from one district to another. The invasion of the Coffee 

 Districts by the destructive Green Scale-bug should prove an objei t- 

 lesson regarding the dangers of importation of insect-pests from 

 one- district to another. In all cases, therefore, when living plants 

 are obtained from a distance, the consignee should insist that the} 

 are properly fumigated before despatch ; otherwise he may after- 

 wards find to his regret, when it is too late that he has p 

 more than he ordered. 



Fig. 54. — " Universal " Ant Exterminator. (Author's original photo.l 



" Ant Exterminators." Several machines have been plai i 

 the market which are intended to pump hot poisonous gases into 

 tin- subterranean burrows or galleries of insects such as termites 

 ami ants. Whilst these are quite efficient in destroying the inmates 

 of Termites' mounds ami of similar nests, they possess this initial 

 disadvantage that, as a general rule, it is not the mound-building 

 termites which do damage and such machines therefore are i 

 paratively of little use in controlling the real culprits whose nests 

 are extremely difficult to discover. It is true that an instrument is 

 available combining a microphone and a pointed iron rod, the 

 being that the rod is thrust into the ground so that, when it ap- 

 proa< Iks a nest, the sound produced by its inmates becomes audible 

 by means of the microphone. But in actual practice, in India at all 

 events, such an instrument is found to be quite use 1 



As noted above, the species of termites which throw up mounds 

 seem to be harmless as a general rule, those which attack hou 

 woodwork and crops belonging to distinct species: but the 

 mound builders often make their nests in the middle of roads, la 

 gardens and similar places where their presence i- able, 



and in such cases the nests are readily destroyed by the u- 

 a special machine. The "Universal" Ant Exterminator cons 

 essentiall) of an air pump I to a small furnace from which 



