4>So 



FAMILY SCOLYTIDAE 



outside, especially beneath the projecting edges of flakes and in crevices, 

 portions should be stripped off and examined on the inside. If, as will 

 be the case when the beetle is numerous, the inner bark and sapwood 

 are found to be riddled with galleries containing larvae, pupae, or beetles, 

 the whole patch affected should be cut out, and the trees either barked at 

 once and the bark burnt, or if the barking is not possible the whole of 

 the cut-out material should be stacked and burnt. Trap trees should be 

 left and watched. 



After the great frosts of February 1905, careful examinations of areas 

 affected, both in the Siwaliks and adjacent sal areas in the Terai and in the 

 Pilibhit forests, showed that the Sphacrotrypes beetle was steadily increasing 

 in numbers in the partially killed and moribund trees. The numbers of 

 these trees were so great that it i-s likely that it will be some years before 

 the beetles begin to find a scarcity of trees to oviposit in. When that 

 date arrives, however, there will be a danger of a severe attack of this pest 

 in the forests unless its predaceous and parasitic foes are able to keep 

 it in check. 



Two insects are known to prey upon this Sphacrotrypes, a histerid 

 beetle and an ichneumon. I think there is a third, 



Parasitic and a clerid beetle allied to Tillictra assamensis (p. 486), but 

 Predaceous Insects. . ... 



1 have never taken it feeding on the bark- borer. The 



histerid beetle Niponius has a wide range in India. 



Bracon sp. This is a small fly, blackish 

 in colour, with two pairs of membranous 

 wings ; antennae and legs are long and 

 slender. The fly probably lays its eggs 

 in the entrance - tunnels of the bark 

 beetles ; on hatching out, the young 

 grubs crawl down the tunnel to the newly 

 hatched bark-borer grubs and parasitize 

 these, either living inside them or on 

 the outside. The bark-borer finally dies 

 of exhaustion, and the braconid grub then 

 pupates, the fly on maturing crawling out 

 of the tree through one of the exit-holes 

 of the beetle. 



Niponius andrewesi, Lewis (p. 102). 



xg 



FIG. 316. 



Bracon sp., parasitic upon 

 trypes siwalikensts, Steb. Siwaliks. 



-Pink in colour, with a yellow head. Elongate and narrow, with twelve body- 

 Length, i in. to iin. It is to be commonly found in the larval galleries of the 

 bark-borer ; it feeds upon the grubs of the bark-borer. 



Elongate, narrow, shining black in colour ; the wing-cases are short, leaving 

 sed the last two segments of the body, which are orange-red in colour. Head deeply 

 Elytra striate-punctate : pygidium punctate. 



