PINE SHOOT-TWISTER. 217 



Oak, the Sessile Oak being comparatively immune), then attacks other 

 broad-leaved trees. Every few years it swarms in great numbers over 

 extensive areas, entirely devouring the pedunculate Oak foliage, checking 

 the growth of the tree, and preventing the ripening of acorns. The eggs 

 being laid on buds and young twigs, caterpillars always begin to feed near 

 the top and move downwards, totally defoliating the tree ; but the foliage 

 is to some extent replaced by the summer flush. 



Wing-span under 1 in., fore-wings pale bright-green, with a whitish or 

 yellowish fringe round lower edges, hind-wings light-grey edged with 

 white-grey. Caterpillar about ^ in. long, 16-legged (10 prolegs), at first 

 grey-green, then dark yellowish-green, with black head and small black 

 tubercular warts with a few fine hairs on the back. Pupa blackish-brown, 

 slender, under ^ in. long. Moths fly in June, and ? lays eggs singly or in 

 small clusters on buds then being formed in the crowns of Oak-trees. The 

 caterpillars hatch out when the Oak-leaves flush in the following May, eat 

 the leaves, and then spin down to the lower foliage, and in June pupate 

 in remnants of leaves rolled together (hence "leaf-roller"), bark-fissures, 

 &c. About three weeks later the moths emerge, pair, and lay their eggs 

 (generation simple and annual). As this insect spends all its life on the 

 tree, and the 9 can fly to lay eggs far and wide, birds form the best check, 

 and should be encouraged to breed in nesting-boxes. When late frosts 

 nip the young Oak foliage during years when the caterpillars abound, 

 these are starved to death. 



* The Pine Shoot- twister, Retinia buoliana, mainly attacks Pines of 

 from 5 to 12 years old growing on poor soil with a warm exposure. 



Wing-span under 1 in.; fore-wings narrow, reddish-yellow, with six or 

 seven broad, wavy, silvery -white, transverse bands, tinged bluish about 

 middle, and with grey-white edging, hind-wings glossy dark-grey, and 

 both pairs with light-grey fringe. Caterpillar 16-legged (10 prolegs), ^ in. 

 long, light-brown, with glossy black head and thorax. Pupa, dirty 

 yellowish-brown, in. long, with a row of fine dorsal prickles. The moth 

 flies in the evening during July, and in daytime rests among needles and 

 shoots of young Pines. The ? lays eggs singly on terminal buds of young 

 Pine shoots of 5- to 12-year-old plantations. Caterpillars hatch out in 

 August and begin to bore, but the damage is hardly noticeable. In 

 September they hibernate in the buds, and in spring the caterpillar, 

 now larger, does greater damage ; but the bud develops partially before 

 the shoot, hollowed out, dies. The terminal bud is hollowed out first, 

 and then the side-buds ; but if one of these escape it becomes the leading- 

 shoot, the bend at the damaged place being still recognisable when the 

 tree is mature. Pupation takes place in June at the base of the hollow 

 tunnelled in the shoot, and moths emerge about four weeks later. 

 Prevention and Extermination. To destroy the caterpillars and pupse, 



