i6 INDIAN FOREST INSECTS 



The buds of Pijius longi folia suffer from the attacks of a cecidomyid fly 

 which causes pseudo-galls to be formed. 



(/) Damage done to the Leaves. — ^Everyone is acquainted with the 

 damage done to the leaves of trees by insects. The result is commonly seen 

 in the ragged edges of partially eaten leaves, in holes eaten out of the inner 

 portions, in the epidermis of the upper or lower surface being eaten, or the 

 parenchyma between the epidermis being consumed or mined by tunnels, 

 in the leaf being "skeletonized," the parenchyma being eaten and the 

 veins left, or finally in entirely defoliated trees. Or again a great web 

 like a gigantic mass of spiders'-webs is seen in the branches of a tree, 

 the leaves in its vicinity being probably mostly stripped off. This, 

 is the home of a society of what have been called the "tent caterpillars," 

 because they thus live together, for a portion of this stage of their 

 existence, in a kind of immense house or tent, usually issuing out to feed 

 at night. 



The insect pests which feed upon the leaves of the forest trees are 

 legion. Some of the more important are now known. For instance, 

 the sal-tree in Assam is at times entirely stripped of all green leaves- 

 over hundreds of square miles of country by species of caterpillars- 

 belonging to the family Lymantriidae {Lyniantria spp.). In the United 

 Provinces the same tree suffers from the attacks of the looper cater- 

 pillar Boaniiia sclcnaria, and from those of the noctuid moth Ingura 

 subapicalis, whilst in the Central Provinces, again, the larvae of the 

 latter and of the moths Lymantria semicincta, Trahala vishnUy and Suana sp. 

 are the worst defoliators of the tree. The defoliation to which the teak- 

 tree is subject from the larvae of the moths Hyblcea puera and Pyrausta 

 machaeralis is well known. Large forests of this tree in the Central 

 Provinces, Bombay, Madras, and Burma are at times completely defoliated,. 

 or the leaves are skeletonized and killed by one or both of these species- 

 working together. 



The deodar in the North-West Himalayan forests is occasionally 

 stripped of its needles by a species of geometrid caterpillar {Gcometrina)^ 

 blocks of forest being completely defoliated. 



The oaks {Quercns incana, Q. dilatata, and Q. seinicarpifolia) of these 

 Himalayan areas are also defoliated by species of Tortrix and Tinea 

 caterpillars, whilst the horse-chestnut is occasionally completely de- 

 foliated by the caterpillars of the moth Acronycta anaedina. The looper 

 grubs of the moth Bistria suppressaria defoliate several species of trees in 

 the Murree hills. 



Again, the oak {Q. lanicllosa) of the Darjeeling forests in the Eastern 

 Himalaya is defoliated by the caterpillars of species of Gazalina. 



But defoliation is not always the result of caterpillar attacks. The. 

 sissu in the Sutlej Valley, and probably throughout the North-West 

 Himalayan valleys, is defoliated by a small weevil named Apoderus (p. 418).. 



