HYLASTES CUNICULARIUS, ER. 29 



It is on this newly-planted area that my observations have 

 been made. 



I believe it to have been infected from the larger, older 

 plantation on which I first observed Hylastes at work in 

 October 1915, for at that time out of seven stumps examined 

 only one yielded Hylastes (and only three specimens at that), 

 all being H. ater. 



In 19 1 6, the youngest plantation was badly infested, and 

 in August one-third of the young plants had been destroyed, 

 chiefly by H. cunicularius. Further, the spruce stumps on the 

 area yielded numbers of H. cnuicularius larvae, pupce and adults, 

 while a few showed galleries containing eggs with the females 

 still at work. The Scots pine stumps, only about twenty in 

 number, yielded H. ater. These facts lead me to believe, as 

 I have said, that the area was infected from the larger, older 

 plantation, but how it was infected I have not been able to 

 discover. 



The plantation then under observation consists of an area full 

 of spruce stumps and roots. Now it is a feature of the spruce 

 that it is shallow-rooted. Its roots do not go deeply into the 

 soil, but extend for long distances just below the soil surface 

 and aie often exposed at certain points. On these roots H. 

 cuntcvlarius must occur in hundreds. I have taken adults on a 

 portion of a root fifteen feet distant from its source at the stump. 

 In this network of infected roots the young conifers have been 

 planted, and the wonder is, not that half of them will probably 

 be destroyed before the year is out, but that any should 

 survive. 



One most interesting feature of this attack must be noticed. 

 After the area in question had been completely felled, the 

 forester took the precaution of burning all the brushwood on 

 the top of the stumps, thus charring them and the exposed 

 portions of their roots considerably. As has been shown, this 

 charring has proved of no avail. The gallery illustrated in 

 Figure i occurred only half an inch distant from a badly-charred 

 section of the root. 



This failure of a much discussed preventive measure is 

 extremely interestmg. At first sight it would seem to indicate 

 that the measure is useless. I am not inclined to make so 

 sweeping an assertion, but I believe rather that charring is 

 useless unless carried out just prior to, or better still, during the 



