138 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



From the above notes it seems reasonable to assume then 

 that the Culbin Sands are, as they are planted, being populated 

 by a fauna derived from that of the near neighbourhood, and 

 this assumption is of interest not only to the naturalist, but is 

 of considerable interest and importance to the forester. It 

 implies that in our older pine woods there is constantly present 

 a fluctuating insect population which, as opportunity occurs, 

 extends its breeding-grounds, and under favourable conditions 

 is capable of reaching considerable numbers and, since it con- 

 sists largely of injurious insects, of causing considerable injury. 



Evidence of this was furnished in a striking manner in study- 

 ing the existing insect conditions on the Culbin Sands. In 

 February of this year (1922) I made a general survey of the 

 felled areas and the odd groups and belts of standing pines, 

 and throughout these the various insects mentioned above 

 were found. The Large Pine Weevil {Hylohius) was the most 

 important insect from the practical forestry point of view, and 

 as the object of my visit to the Sands was to assist in protecting 

 the new plantations being formed, it naturally received most 

 attention. In February only larvae of Hylobius were found, 

 but their general occurrence throughout the area was roughly 

 mapped out. 



A second visit to the Sands was made in early May, when 

 Hylobius and its associates were beginning to be active, and the 

 following observations indicate in a striking way what has 

 happened and is happening on this area. On the borders of 

 a felled area near the Snab of Moy several young planted pines 

 had been freshly nibbled by the weevil, and further east an 

 isolated self-sown pine about 3 feet high had been severely 

 o-nawed. No weevils were found on it, but on raking in the 

 sand immediately around it 44 specimens were obtained. Some 

 hours later 8 more were found, and on the following day 

 another 10 were taken. On trees forming scattered groups 

 throughout the western portions of the Sands the signs of weevil 

 work on the branches and twigs were evident, and under one 

 pine about 15 feet high 65 weevils were collected in the soil. 



These observations indicate the normal or original mode of 

 life of Hylobius. It is an inhabitant of standing pine woods, 

 breeding on snow broken or wind-broken branches, or in the 

 roots of pines dying from one cause or other, and it feeds on 

 the young twigs in the crevices of the living trees. Altum, 



