FAMILY SCOLYTIDAE 559 



From observations made in October and November 1906 in Jaunsar and 

 Tehri Garhwal, and others undertaken in May and June in both Jaunsar and 

 Kumaun, it would appear that the insect commences to lay the eggs of the 

 fir-st generation of the year some time early in April (or perhaps towards the 

 end of March), the beetles hatching out from these eggs appearing towards 

 the end of May, a couple of days being passed in the egg stage, some five to 

 six weeks in the larval, and ten days to a fortnight in the pupal condition. 

 Allowing from six weeks to two months to a generation, a second generation 

 of the beetles would issue towards the end of July, and a third towards the 

 end of September, which would lay the eggs of a fourth generation, which 

 may either hibernate as larvae in the trees or go on to the mature stage 

 and pass through the winter as beetles. In favourable years this fourth 

 generation may be completed, and may lay the eggs of a partial fifth gene- 

 ration. For instance, on u October, at a fairly high elevation in Jaunsar, I 

 found the beetles of the third generation issuing and egg-laying, or nearly 

 mature. On 3 November, at a much lower elevation, in the Tons Valley in 

 Jaunsar (at Thadiar), I found the beetles of the fourth generation maturing. 

 These beetles were issuing to deposit in the trees the eggs of the fifth 

 generation of the year. 



I first noticed old traces of the attacks of this insect in June 1902 in the 

 Tons Valley, Jaunsar, and found one dead beetle. In October 1906 I took 

 the insect numerously at Jermola and elsewhere in Jaunsar and Tehri 

 Garhwal, and in May and June 1908 I took the insect in the Kumaun 

 V. longifolia forests. In June 1909 I found the beetle in chir-trees in the 

 Ravi Valley in Chamba. 



As far as present observations show, this Tomicus only infests the Pinus 

 longifolia in the pole and older-growth stages. I have 

 Damage Committed not taken the insect in seedlings or saplings, nor in the 

 in the Forest. thinner branches of the crowns of the larger trees. The 

 insect must be classed as one of the more dangerous of 

 the pests of the tree. It only infests green trees, either newly felled or blown- 

 down ones, or sickly standing ones in the forest. I have taken it attacking 

 green trees in company with Cryptorhynchus brandisi and Polygraphus loji^i- 

 folia. Its presence when in any numbers can easily be detected from the 

 outside, owing to the fact that it ejects from the entrance-hole small cylinders 

 or heaps of light red and yellow sawdust, these little heaps being distinctly 

 visible on the rough red bark of the tree. Once the insect has infested a 

 tree in any numbers, the death of the tree is a certainty. Owing to tin- 

 long egg and larval galleries eaten out, and the winding m in ner in which 

 the latter are taken, little of the inner bast layer of the tree is left intact, 

 the untouched portions consisting merely of small ridges and rirns of bast 

 between the mass of excreta-filled galleries. 



The attacks of such an insect are naturally the more to be feared in a 

 pure than in a mixed forest. 



