12 



INDIAN FOREST INSECTS 



protects them from the attacks of the 

 gall-making insects and from the 

 tapping operations of the plant-lice 

 (aphids) and coccids or scale insects, 

 and from the attacks of the bark- 

 eating caterpillars, which can only 

 attack the softer parts of the tree. 

 In many cases the thinner bark, 

 leaves, flowers, and seeds contain 

 substances such as unpalatable sap, 

 oils, etc., which are distasteful or 

 inimical to insect life, such trees 

 proving more or less immune to 

 serious attack. 



We turn now to consider briefly 

 the damage which may be done to the 

 individual parts of the tree. 



Fig. 8. — Root of .haa'a arabica tunnelled 

 by Coelosterna scabrata. ISectle /;/ 

 situ in pupal chamber. Berar. 



(a) Damage done to the Roots. — 



Probably greater damage is done to 

 the roots of forest trees in India than 

 the forester has as yet any suspicion 

 of. The thicker roots of the sal- 

 tree are subject to the attacks of 

 Cerambycidae {Hoploceranibyx, p. 320) 

 and, in the portions contiguous 

 to the trunk, of Scolytidae {Sphaero- 

 trypes, p. 481), whilst the bark of 

 the smaller roots is eaten by various 

 species of Melolonthinae (Cock- 

 chafers, p. y^). 



The roots of young seedlings and 

 saplings of another broad-leaved tree, 

 the babul {Acacia arabica), are tun- 

 nelled into and destroyed by a cer- 

 ambyx beetle {Coelosterna, p. 358), 

 whilst those of young poplar saplings 

 are tunnelled by the caterpillar of a 

 moth {Trochiliniii oiniiatiacfonne), and 

 those of the sandal-wood {Santahim 

 album) by another lepidopterous cater- 

 pillar {Zeuzera coffaea). 



The roots of deodar seedlings 

 are cut through by the coleopterous 

 wireworm {Elater, p. 230) and the 



