Insect Enemies of Trees 207 



mens in the immediate neighbourhood were badly infested. 

 This was particularly noticeable on some park trees on two 

 estates that I visited lately ; in each instance the majestic 

 boles rose to a height of fully 90 ft. and contained about 100 

 cubic ft. of wood. At one time I had an idea that beech 

 trees when grown too thickly were most liable to be attacked, 

 but more extensive observations have disproved the hypo- 

 thesis. By some it has been suggested that the drainage 

 of ground on which the beech is growing will facilitate the 

 spread of the insect by bringing about an unhealthy state 

 of the trees. To some extent this has been noticed at Burn- 

 ham, and particularly in Gloucestershire, where a lake had 

 been formed contiguous to a beech plantation. In another 

 instance that came under my notice the burrowing of rab- 

 bits to an unusual extent was blamed for the appearance of 

 the insect and the gradual death of the trees, the soil in this 

 case being sand and gravel. It is a strange fact, too, that a 

 badly infested tree may be standing amongst others that are 

 perfectly free from the attack. Under a magnifying glass 

 the insect appears of a yellowish colour, irregularly globular 

 in shape, and almost transparent. It is thickly covered 

 over by a secretion from the body, which looks like fine 

 waxen-white threads or cotton wool, which effectually 

 screens the insect from observation. With its proboscis it 

 sucks up the juices, which are readily reached through the 

 thin, smooth bark. When badly attacked, the foliage be- 

 comes meagre and has a burnt appearance, then the tips of 

 the branches, and finally whole branches die off. After- 

 wards the bark becomes dry and cracks, usually longitu- 

 dinally, falling off in flakes with the death of the tree. The 

 timber of trees that have been killed by the coccus is dry, 

 short-grained, and by no means comparable with that of 

 healthy specimens. From whatever cause, the presence of 

 the insect in our plantations is much to be deplored, and 

 already many fine old trees in different parts of the country 

 have succumbed to the attack. It is a curious fact that 

 certain trees fall victims to the attack of this insect very 

 rapidly, often in the short space of two years, while others 

 of equal age and vigour, and, as far as can be seen, similarly 



