262 FOREST ENTOMOLOGY. 



The larvas are a slaty colour. The head is a dark-bronze colour, a 

 shade darker than the body, but not so dark as the shield of the head. 

 On each segment may be found four minute black spots, which become 

 more pronounced as they get older. When full fed they measure 

 about yi of an inch in length. They curl up the leaves for shelter, 

 feed most voraciously, and when disturbed lower themselves by a 

 slender thread. 



The pupa is of a uniform dark - brown colour. Pupation takes 

 place in the folds of the leaves, and the moths appear in swarms 

 about the end of June. 



The moth is easily identified, as it is the only pure green Tortrix 

 we have. The fore wings are pure green, hind wings grey. Head, 

 antennae, and body yellowish- white. Wing-span about 22 to 24 mm. 



This species, as has been asserted, is very injurious to the oak, 

 but it should be noted that it is more injurious to the pedunculate 

 than the sessile variety. As regards the discrimination of those two 

 varieties, practical men as well as botanists do not quite agree ; but 

 it may be said that distinct types are easily determined. The par- 

 tiality of the insect for the pedunculate variety was pointed out to 

 me by my friend Mr J. F. Annand in the Chopwell Woods, Co. 

 Durham. In this case the pedunculate variety was entirely 

 defoliated, whereas the sessile variety was untouched. This 

 peculiarity is noted by Mr Elwes, in his magnificent work on ' The 

 Forest Trees of Great Britain and Ireland,' in the following 

 remarks : 



"Another peculiarity of the sessile oak is referred to in a letter 

 from the Hon. Gerald Lascelles to Mr Stafford Howard, in which 

 he says : ' I doubt whether there is much difference between the 

 timber of the sessile and pedunculate oaks, but I think that the 

 sessile is straighter and cleaner in growth, and one thing is certain, 

 that it is almost immune from the attacks of the caterpillar (Tortrix 

 viridana) which so often destroys every leaf on the pedunculate oak 

 in early summer. Whether this does any real harm or not is a moot- 

 point, but I think it must be a check to growth, and that the trees 

 would be better without it. I have seen a sessile oak standing out 

 in brilliant foliage when every tree in the wood around was as bare 

 of leaf as in winter.' 



" Mr J. Smith, in the paper above referred to, pp. 29, 30, confirms 

 Mr Lascelles' observations, and says that in 1888, which was the 



