2O 



INDIAN FOREST INSECTS 



Small bast-living forms of the Staphylinidae also prey upon various 

 scolytid b:irk-borers or their grubs. 



Many of the Coccinellidae are active predators 

 both in the grub and beetle stage. For instance, 

 the coccinellid Vedalia (p. 125) preys upon the sal 

 coccid scale insect Monophlebus stebbingii, whilst 

 the cosmopolitan Coccinella septempunctata (p. 123) 

 preys upon the Aphis of the blue pine, the 

 Lachnus of the silver fir, and upon the young grubs 

 of the Chermes himalayensis. 



The beetle Cissites (p. 248) oviposits in the 

 tunnels of the carpenter bee, Xylocopa latipes, in 

 pyinkadu, its grubs feeding upon those of the 

 latter. 



Finally, to come to the Rhynchota, the bug 

 Erthesina fullo feeds upon the caterpillars of the 

 sal-defoliator Boarmia selenaria in the United 



FIG. 13. Hectarthrum uni- Provinces Terai forests. 

 forme, Waterh., which 



Er"VS In (*). PARASITES, OR INSECTS WH.CH LIVE PARASITI- 



Tenasserim. CALLY UPON INJURIOUS SPECIES, SLOWLY 



KILLING THEM. 



The number of insect parasites, as also of that far less-known branch, 



the fungus parasites, of the insect world is very great. The forester, and more 



especially the forester in India, where the individual charges are of such 



vast size and the forests of such enormous extent, is very largly dependent 



upon the parasites which decimate and keep in check the insect foes of 



his trees. It is therefore of considerable importance that he should be 



able to recognize the presence and abundance of such valuable coadjutors 



in his work of protection. That this is by no means a difficult feat will soon 



become evident to the forest-trained eye. One has only to repair to a felling 



area, and carefully scrutinize felled trees which have been lying in the 



forest from two to three weeks with the bark on. The presence of various 



bark-borers will soon be noted, intent on tunnelling into the tree to eat 



out their egg-galleries in which to oviposit, or crawling over the bark 



searching for a favourable spot to start their tunnelling operations. In 



the Western Himalaya the predator Thanasimns may be noted flying round 



or running quickly up the bark, searching eagerly for the bark-beetles. 



Watch closely and you will see numbers of minute flies hovering about, or 



settling upon the bark and disappearing down the entrances to the tunnels 



made by bark-beetles who have already got well down through the bark 



and reached the bast. These flies are parasitic insects, the friends of the 



forester. They creep down the tunnels of the bark-borers and lay their 



eggs in the galleries in the bast. The young grubs, on hatching from 



these eggs, feed parasitically upon the grubs of the bark-borer, clinging 



