SOUTH AI'MIIOAN I5AG\V0I|]VIS. 659 



we iind in a young plantation tliat a single tree or group of 

 trees has become thoroughly infested, the remainder of the 

 plantation or block being free from bagworms. The most 

 plausible explanation therefore is that a hare or buck, passing 

 through the web-covered brushwood, has carried a consider- 

 .able number of bagworms with it, and entering the plantation 

 of young ti-ees near by has rested in the grass at the base of 

 one of the trees, and the bagworms have crawled off the carrier 

 and ascended the tree or trees in its immediate vicinity. 

 Such cases we find in blocks of youag trees where the canopy 

 is not yet formed and there is a great deal of grass growing, 

 which would afford shelter and a hiding place during the day 

 to such an animal. As the trees are accessible to light all 

 around, the bagworms do not in response to their phototi'opic 

 instinct ascend the tree to the top, but feed on the ends of 

 the branches, and we find the tree infested with bagworms 

 from top to bottom. Several such centres may be found in 

 one block, showing the spots where the carrying animal had 

 sought a temporary halting or resting place. 



Both these local bird and sporadic infestations may act as 

 centres for the spread of the insect in a new locality, and in 

 the course of a few years may increase to a more general 

 infestation of the entire block. This is what we have termed 

 an accumulative infestation, as distinguished from the 

 general or gross infestation, caused by wind as the carrying 

 -agent. By the wattle growers the two are often confused, 

 because the beginnings of an accumulative infestation are not 

 noticed, and it is only when the block becomes thoroughly 

 infested that attention is drawn to it, and this is then de- 

 scribed as a sudden appearance of the bagworms in enormous 

 numbers. We are generally able, however, to prove the 

 -accumulative nature of the infestation by the presence of old 

 bags scattered over a few centres in the plantation. 



C. Instincts developed in connection with the 

 protection of the larva. — These find their expression in 

 the formation of a bag as a protective covering during the 

 feeding period of the larval life, and the gregarious habit 



