FAMILY SCOLYTIDAK 



595 



out the grubs appear to feed close together side by side, eating out a broad 

 gallery or tunnel in the heart-wood whose direction is at right angles to the 

 mother tunnel, the gallery taking off from the bottom of the mother tunnel. 

 This broad gallery made by the larvae gradually increases in width with 

 their growth. On reaching full size the grubs pupate /';/ situ, and from the 

 pupae the beetles gradually mature. 



At the beginning of February these broad larval galleries each contained 

 from twenty-five to thirty beetles in them just maturing or mature. This 

 would indicate that each female lays at least twenty-five to thirty eggs. 



The heart -wood of the tree examined contained a number of the broad 

 larval galleries, from the narrower end of which the egg-tunnel took off at 

 right angles, running up into the sapwood and bark. 



FlG. 374. Egg-tunnel and larval gallery of XyL'/'orn.t parvulus, Eichhoff, 

 in the wood of Biichanania latifolia. A, gallery made by larva in heart-wood (/), 

 with base of egg-tunnel (e] ; B, egg-tunnel (e) and larval-gallery (7). Siwaliks, 

 Northern India. (K. P. S.) 



The egg-tunnel had evidently been eaten out and the eggs laid in the 

 autumn of 1905, and the beetles arising from these eggs would issue about 

 March or the beginning of April. 



I have not yet ascertained how many generations the insect passes 

 through in the year. 



The chief importance of this insect is in the damage it causes to the 

 heart-wood of the tree. In the case examined the 



Damage Committed who j e of thfi timber was wor thless for anything Save 

 in the forest. 



firewood. When the insect attacks a tree in the 



numbers here observable it also weakens it owing to the- large number of 

 holes riddling the cambium layer. The tree in question had died, and every- 

 thing pointed to the fact that the beetles had killed it. 



The Buchanania is of some importance in the Sivvalik Forests, as it 

 helps the sal-tree to cover the ground and thus prevent denudation and 

 impoverishment of the soil. 



I calculated that some 10,000 to 12,000 beetles at least were destroyed 

 in the infested tree examined, which I had felled, cut up, and burnt. 



p p 2 



