ij66 C. B, HARDKNBEKU. 



extent, as in every plantation known to me, where the fungus 

 is well established, heavy losses due to bagworm injury still 

 occur. This appears to be mainly due to the circumstance 

 that when the bagworm s begin to attach themselves they do so 

 as a rule fairly low down on the trees. When the spores are 

 being produced from the infected bags they, in order to be 

 effective, must reach the young bagworms on the tops of the 

 trees, where they are feeding at that time. The spores must 

 therefore be carried up, and this probably occurs only under 

 exceptional circumstances. This is presumably the i-eason 

 why the majority of the bagworms become infected only at a 

 later stage in their larval life when they are feeding on the 

 lower branches of the trees. For these reasons the fungus is 

 not as effective as otherwise it might be. 



Actual counts of some twenty thousand bagworms, gathered 

 in an infected plantation, showed that of the bagworms which 

 reach the resting stage the maximum of fungus-infested indi- 

 viduals was only 22'5 per cent, of the total number. This 

 was in a plantation where the fungus had been well estab- 

 lished, and which was suffering from a gross infestation of 

 bagworms for the third consecutive season, conditions Avhich 

 would seem to be vei'y favourable to promote the maximum 

 efficiency of the fungus. This percentage is, of course, not 

 high enough for the effective control of the bagworm by this 

 means alone. 



Other diseases. — Besides the fungus there are many 

 other diseases to which the bagworm is subject. Most of 

 these are as yet of an unknown character, but are probably 

 of an intestinal nature. One of these, which we have re- 

 peatedly noticed in the laboratory, causes constipation of the 

 larva with an untimely death as the ultimate result. The 

 caterpillar generally succumbs at a very early age. 



Another disease is more of the nature of dysentery, and 

 appears to be induced by the consumption of wet food. It is 

 especially prevalent amongst the young bagworms, and is 

 probably the cause of the death of so many after a prolonged 

 wet spell. We have noticed that the bagworm stops feeding" 



