48 



INDIAN FOREST INSECTS 



bark is stripped off, and fly off and infest fresh trees in the forest. The 

 periods will, of course, vary with elevation, aspect, etc., and be a little later 

 in wet cold seasons ; but the time can always be accurately determined by 

 stripping off a piece of bark and examining the larval galleries on the inside 

 to ascertain whether they have nearly reached their normal length. If they 

 have, the full-grown larvae or pupae will be found at the end or in the sap- 

 wood beneath, and the time has come to bark the trees. 



In the case of the bark-boring Scolytidae, stripping off the bark and 

 burning it will be sufficient to destroy the insects, as they mostly pupate in 



the bast or partly in the bast and partly in 

 the sapwood. The fact of taking off the 

 bark and exposing them to the heat of the 

 sun or cold at night is sufficient to kill the 

 larvae and pupae, although it will not kill 

 immature beetles. 



The buprestids and cerambycids 



tl jT* L pupate in the sapwood, and the wood- 



■ K I boring Scolytidae, etc., oviposit here or 



Ml ^1 right dow^n in the heart-wood. To get rid 



of these the trees must be logged and the 

 logs burnt. 



I 



(2) Wood-borers in Timber Stacks, 

 Fuel Stacks, and Bamboo Piles in Depots. 



Wood stacked in depots or out on the 



IJP i I forest roads and rides, if left for any time, 



t, |l| i 7 ^^ subject to the attacks of various boring 



^M beetles, of which species of Bostrychidae 



I I are amongst the worst in India. Some of 



■ ^- ' the Scolytidae also do damage in this way, 



and a few Cerambycidae. As instances of 

 damage of this nature, the genera Sinoxylon 

 and Dinoderiis in the first family, Xylcborns 

 in the second, and Stromatinm amongst 

 the Cerambycidae, may be quoted. The 

 females of all these insects tunnel down into wood, usually when the first 

 sap has dried out of it, to lay their eggs. On hatching out the grubs feed 

 in the wood, reducing its structure to powder. Or in the case of some 

 Scolytidae the damage is solely due to the wood becoming excessively 

 "shot-holed" from the number of the beetles boring in to oviposit, and 

 thus ruined for timber purposes. 



Finally, in the case of some of the cerambycids who lay their eggs on 

 green trees, the grubs may have tunnelled into the heart of the timber to 

 pupate, and be there or engaged in this operation after the timber has left the 

 forest for the depot {/Eolesthcs, Hoplocerambyx). 



Fig. 25. — Pupal chambers of Hoplo- 

 ceratnliyx spiiticortiis in heart- 

 wood of sal-tree (much reduced). 



