314 FAMILY CERAMBYCIDAE 



Euphrates poplar {P. cuphvatica), Kandahar willow {Salix alba), weeping- 

 willow (5. babylonica), chinar {Platanns orientalis) (only slightly), and the 

 elm {Ulmus sp.). The black poplar, Kabul willow (5. aemophylla) , ash, 

 mulberry {Morus alba), apricot (Prunus armcnica), horse chestnut (Aesculus 

 indica), and robinia {Robinia pseudo-acacia) were not attacked by the beetle. 



The two stages in the life of this pest during which actual damage 



is done to the tree are the beetle and grub ones. 



Damage done to the bounds, such as those made by lopping branches, 

 Tree; Methods of , . , . i i 



detecting it. abrasions dunng storms, etc., are taken advantage of 



by the female beetles for laying their eggs in. Failing 

 fresh wounds on the bark, the beetle has to bore through the trunk down to 

 the sappy portion of the bark in order to deposit her eggs in a position to 

 ensure there being an abundance of soft food for the young larvae on 

 hatching out. After feeding upon this for a period, the grubs, as they 

 become older, work their way into the bast and sapwood of the tree, sub- 

 sequently proceeding down into the wood to pupate. It is in the former 

 stage of its life that the insect effects the greatest damage to the tree. An 

 examination of many trees in Quetta in 1905 showed that owing to the feed- 

 ing of the grubs beneath the bark the larger part of the green bast is eaten 

 away by the larvae. Now, if the grubs are at all numerous in the tree, these 

 eaten-out patches gradually join all round the stem, and the result is that the 

 tree is ringed and dies. Even with the insects as plentiful as they were in 

 Quetta between igoo and 1905 the trees took some time to die, and this must 

 be attributed to the fact that the beetles will lay their eggs on any part of the 

 stem from the base up to the crown, in fact as high as there is a sufficient 

 thickness to ensure there being a sufficiency of wood for the insect to bore 

 into to form its pupal chamber. Owing to this fact, it takes longer for the 

 patches eaten out by the larvae to coalesce all round the stem in one band, 

 and the tree only dies slowl}', as is shown in the case of the willow depicted 

 in pi. xxi. At first sight this prolongation of the life of the tree might be 

 considered an advantage, since it gives time for the growth of others to 

 replace it. In reality, however, the position of affairs is very different. 

 Trees so infested merely serve as centres of infection for neighbouring 

 unattacked trees, and the insects will go on laying in them until the trees 

 have arrived within a year of death. No beetle will then oviposit in them, 

 since an abundance of fresh sappy bark and wood is essential for the grub's 

 food. Cutting out dead trees, therefore, has absolutely' no effect one way 

 or the other in mitigating the damage done by the pest. 



The detection of infested trees is comparatively simple. 



(a) Seriously Affected Nearly Dead Trees or Dead Trees. — These are 

 easily recognized. Large areas of the bark will have fallen away, disclosing 

 the wood beneath deeply scored with the galleries of the larvae, some of 

 which may be still filled with the large masses of chewed wood and fibrous 

 excreta. If this latter has already fallen from the galleries, the pulling off 



