54 8 FAMILY SCOLYTIDAE 



ever, requires further careful observations to be carried out between July 

 and the close of the year. The eggs of the May generation of the beetle 

 are probably laid in the trees early in April by beetles which have either 

 passed through the winter in the tree or have hibernated as larvae in the 

 larval galleries in the bast, subsequently maturing and issuing as beetles as 

 soon as the first warmth of spring makes itself felt. 



At present I have only taken this insect in full-grown and old oak trees, 



but it apparently attacks both the moru and ban oaks. 



Damage Committed Th d t be feared from the insect is due to its 



in the Forest. ^ 



habit of ovipositing in the bast layer of the trees. As 



has been shown, the operations of the beetles and their larvae lead to 

 the destruction and disappearance of the bast, and when the insects are 

 numerous end in the death of the tree. In several instances the death of 

 large trees examined appeared to be due directly to the attacks of this insect. 



Its greatest danger is, however, evidently to be found in the fact that 

 it forms such a powerful ally to the Loranthus vcstitus parasite which infests 

 the oaks. Broad-leaved trees are much more resistant to the bark-boring 

 beetle attacks than is the case with conifers, and consequently it is probable 

 that the oak can ordinarily hold its own against the scolvtid. 



It is essential to the latter that the bast layer of the tree should be 

 fresh and sappy ; but the beetle invariably seeks out diseased trees, or 

 those which have become weakened through some cause, in which to lay its 

 eggs. The slow strangulation and consequent weakness set up in the trees 

 by the Loranthus parasite places the tree in the exact condition preferred 

 by bark beetles, and where these insects are at all numerous an attack in 

 Lom/ms-weakened trees may be looked upon as a foregone certainty. 

 Once the insects have obtained a hold in a forest their powers of rapid 

 multiplication render them a pest which has to be reckoned with. 



Protective and remedial measures for safeguarding the uninfested trees 



in Naini Tal and elsewhere have been briefly considered 



Remedial Measures. un ^er the longicorn beetles Lophosternus hiigclii and 



Xylotrcchus, stcbbingi (pp. 275, 351). It will be well, 



however, to glance at measures applicable to this insect alone, since it is 

 probable that very often it infests the tree before thebuprestid orcerambycid 

 pests make their appearance. 



To combat these bark-borer pests adequately it becomes necessary to 

 know the exact life history of the insect, and more especially in what 

 months during the year it is in its larval stage, for it is in this stage that 

 it can be best attacked. When the tree is full of nearly full-grown larvae, 

 it should be felled and barked and the bark burnt. From the life history as 

 at present observed we know that this can be done at the end of the first 

 week in May for the grubs of the first generation and at about the end of 

 June for those of the second generation. 



Further, both as a means of discovering the number of insects in a 

 forest and as a means of protecting that forest as well, "trap trees" should 



