292 



CO>'TROL OF WATTLE BAGWOEM. 



liatching' place." He also records tlie fact lliat the young 

 bag-worms are preyed upon by several species of jumping' 

 spiders, Attidae, just after leaving' the parental bag'. 



The young larvae are dispersed by wind, bird and insect 

 agency, and many of them must die of starvation through 

 being carried away to places where they cannot find suitable 

 food. Those that survive these early perils and manage to 

 construct their bags enjoy a certain amount of immunity for 

 a time, as they are small, inconspicuous, and well protected 

 from their minor enemies. Later in the season, however, the 

 bags are conspicuous objects, and numbers of the larvae fall a 

 prey to birds and rats. The birds that prey upon the bagworm 

 include sprews (Pegler), parrots, weaver birds and the little 

 silver-eyed bird of the thorns (Fuller), the yellow Aveaver bird 

 and the butcher bird (Hardenberg). These birds pluck the 

 larvae out of the bags whilst they are feeding'. The rats 

 {Mus coucha and M. natalensis, according to Hardenberg) 

 tear open the bag" with a, characteristic semicircular 

 slit and extract the larvae and pupae through the 

 holes thus made. Hence, in a lot of bags collected 

 in a plantation one can determine witli a fair amount 

 of certainty how many larvae have been destroyed by 

 birds and how many by rats. The number of emj^ty bags 

 that are clean and unsoiled (the bagworms will leave soiled 

 bags of their own accord) give an idea of the number of larvae 

 that have been eaten by birds, and those that have been torn 

 open give the number destroyed by rats. The figures below are 

 not a true guide as to the numjber of larvae killed by rats, as 

 the rats generally remove the bags from the trees before 

 tearing them open, and the bags included in the counts were 

 all gathered from the trees. 



From the above figures it would seem that rats and birds 

 are practically negligible as factors in tlie control of the wattle 

 bagworm. But, in addition to the fact that the totals do not 



