FAMILY SCOLYTIDAE 565 



the end of the larval gallery a little enlargement is made, and the larva 

 changes into a pupa in this, the latter turning in due course into a beetle 

 and boring its way out of the branch. 



This little beetle confines its operations to the smaller branches of 

 the coniferous tree attacked, where the bark is still quite soft. It infests 

 these places in enormous numbers, working in company with the larger Poly - 

 gr a pints (P. major, p. 501). It is to be found in the side branches and upper 

 portion of the leading shoot of older saplings. In smaller ones it infests 

 every part, and it then becomes a serious pest, as it would appear to have 

 the power of increasing in large numbers. Its attack can be recognized from 

 the outside by the small pin-holes seen in the bark, each surrounded with a 

 small white ring of resin ; the bark when very young turns yellow under the 

 attack and shrivels up. The arms of the stellate galleries run longitudinally 

 up and down the stem rather than horizontally, and the plans of the 

 pairing-chamber and egg-galleries are not unlike those of P. major, with 

 which they are often found mixed up and interlaced. The latter are, 

 however, larger, have longer arms, and the egg-galleries are fewer in number 

 and go much deeper into the sapwood, this being more especially noticeable 

 in the case of the smaller branches attacked. 



I have found this Pityogenes in company with Polygraph-its major infesting 

 deodar saplings. It was very numerous in the tops of saplings at Pajidhar 

 in Jaunsar in June 1902. In a few cases it was found in the main stem, 

 low down, and the gallery had then only four arms or egg -galleries to it, the 

 pairing-chamber being made entirely in the bast, as also were the larval 

 galleries and pupating-chamber, only the egg-galleries grooving down into 

 the sapwood. In the tops, however, and leading shoots the attack corre- 

 sponded in all respects to that in the blue pine. I was unable to count the 

 number of egg-galleries bored, as the bark and sapwood were riddled by 

 the interlacing galleries. All the stages of larva, pupa, and beetle were 

 found, and also mature beetles just boring into the stems to lay eggs. This 

 would seem to confirm my theory that the generations in one year of the 

 life history of this insect overlap one another, since it would seem probable 

 that the larvae were those of the second generation, the first lot of grubs 

 appearing somewhere about the beginning of May. This would mean that 

 the August-September larvae are those of the third generation, and the 

 November beetles those probably of a fourth, which lay the eggs of the 

 beetles which issue at the end of April in the following year. The 

 Pityogenes was equally numerous in the neighbouring blue-pine saplings. 

 As in the case of P. major, the fact that this beetle attacks the deodar in 

 addition to the blue pine greatly adds to the importance of the pest, and 

 renders it essential that its life history should be understood. 



I found that a number of the dead deodar-trees killed during a bark- 

 beetle attack in the years 1907-1908 and rxamined in the forests at Bre in 

 Chamba in 1909 had been badly infested by this beetle, which had evidently 

 sw.irmed in large numbers. 



