6o6 



FAMILY SCOLYTIDAE 



Occasionally, as shown in pi. Ixi, they may all take off on one side. In 

 these the eggs are laid. On hatching out, the grubs feed upon the sap 



on the walls of the tunnel, or on 

 fungus outgrowths growing there. 

 By the time the grubs are mature 

 the walls of the offshoot tunnels are 

 deep black in colour to a depth of 

 one-twentieth of an inch. 



When full-fed the grubs pupate 

 in situ in the offshoot tunnels, 

 there being at least two eggs laid in 

 each of the latter. On maturing, 

 the beetles leave the tree by crawl- 

 ing out of the offshoot tunnel into 

 the main gallery, and up this to the 

 pairing-chamber, and then burrow 



FlG. 385. -Egg-gallery of Scolytoplatypus 

 himalayensis, Steb., in the wood of silver 

 fir. Chamba, North-West Himalaya. 



out through the bark. 



I found some of the beetles which had just matured in the blown 

 pole tunnelling into a newly blown silver-fir close by, laying what were 

 probably the first eggs of the year at this elevation (8,500 ft.). It is doubtful 

 whether there is a second generation in the year, but it is possible that 

 the June eggs may give rise to a generation of beetles by the following 

 September. 



This scolytid is one of the most injurious insects I have yet found 



infesting the wood of the silver fir. The tree appears 



Damage to Tree. to be singularly free from a number of the bark and 



wood beetles which infest the other conifers of the 



Himalaya region to so serious an extent. It is impossible at present to say 

 whether the insect is in any abundance in the Western Himalaya. I have 

 only taken it on one occasion, but the wood of the tree in which I took 

 it was riddled to a very serious extent, and useless for any save firewood 

 purposes. 



'1 he genus is an interesting one, having been founded by Mr. W. F. H. 

 Blandford on two specimens from the Himalaya (S. raja) (one in the 

 I'-ritish Museum and the other in the Brussels Museum), and four others 

 obtained by Mr. G. Lewis in Japan. To the forester the importance and 

 interest of the genus lies in the fact that it forms a connecting link between 



Scolytidae and the Platypodidae, and that its habits are wood-boring, 

 it thus resembling the Xylcbori and platypids in this respect. 



