44 INDIAN FOREST INSECTS 



II 







It is not possible, however, to 

 obtain a previous warning in all 

 cases. For instance, the Mono- 

 phlcbus sal scale, which infests the 

 sal in the Siwaliks and United 

 Provinces sal forests, generally 

 affords, so far as is at present 

 known, no such previous evidence 

 of a bad attack such attacks, e.g., 

 as were experienced between 1898 

 and 1902 in this region. 



The forester is on safer ground 

 when he wishes to ascertain the 

 abundance in the forest of the 

 bark- and wood-boring pests of his 

 trees. It is always possible for him 

 to keep himself posted with practi- 

 cal certainty on this point. If you 

 walk through a wood in Germany 

 or France you will find felled green 

 trees at intervals lying to one side 

 of the road or path. These trees 

 have been felled with the express 

 purpose of enabling the forest officer 

 to keep himself informed as to the 

 presence of and abundance of the 

 bark-boring and timber-boring in- 

 sect pests which infest the parti- 

 cular species of tree of which his 

 forest is composed. By cutting off 

 a square of bark at the period at 

 which he knows the insects will 

 be on the wing in the forest, he 

 will be able at once to ascertain 

 their abundance. For both bark- 

 borers and wood-borers will resort 

 to these freshly felled trees to ovi- 

 posit instead of searching for sickly 

 trees or fresh windfalls in the forest 

 itself. He will, therefore, find these 

 insects at work boring through the 

 bark to oviposit in the bast, or tun- 

 nelling: down into the timber to 



FIG. 24-Interior of section of a stem, showing la y. their e Sg s there ' lf at 

 pupating-chambers of a longicorn beetle. period he finds these trees full of 



