SOUTH AFRICAN BAGWOEMS. 657 



lias several times, while walking in the evening, found a 

 number of bagworms attached to his clothing, which could 

 •only have settled in this manner. On another occasion it was 

 found that some four dozen young wattle trees, grown in tins 

 on the laboratory grounds for experimental purposes, had 

 become thoroughly infested overnight with young bagworms ; 

 the nearest plantation, or food-plants, on which these could 

 have hatched being a couple of miles away. In this way we 

 must account for a sudden general or gross infestation 

 of a new plantation or block Avhich had previously shown no 

 signs of bagworm injury. 



It sometimes happens, but su^ch cases are rare, that the 

 young bagworms are forcibly driven before the wind into 

 another plantation near by. When this happens we find that 

 the first few lines of trees have become grossly infested, the 

 infestation becoming thinner and thinner as we penetrate 

 deeper into the block. Only one such lateral or side 

 infestation has come to the writer's notice, the manner of 

 infestation being such as to leave no room for any other 

 explanation. Evidences of this will be, of course, more con- 

 clusive when the wind has struck the block atlnvart the rows 

 of trees ; if the wind passes through the plantation in the 

 direction of the rows the bagworms may be carried inward 

 for a considerable distance, or even the entire length of the 

 rows, and the distinctive type of such an infestation will be 

 lost. 



The heavy wind-storms, which are so prevalent during the 

 late winter and early spring, may even carry the young bag- 

 worms after they have made their bag. During the first few 

 days after the bag is made the young bagworm feeds on the 

 upper surface of the leaf and is rather loosely attached. The 

 writer has seen such small bags dropping out of the sky in 

 the same manner as the naked caterpillars. 



(b) Birds. — It is evident that on account of the exposed 

 position of the young bagworms there are many opportunities 

 for them to attach themselves to the feet and plumage of a 

 bird resting temporarily in the trees of an infested plantation. 



