SOUTH AFRICAN BAGWOBMS. 667 



duving' a rain or mist, and only starts again after the foliage 

 has dried. The older bagwornis can withstand starvation for 

 a considerable time, and can thus safely pass through a rain 

 or mist of several days' dui-ation, but the young cannot starve 

 as long. If there be a prolonged period of continuous rain 

 or mist, so that the foliage has no chance to dry, the young' 

 larv« are by hunger compelled to eat wet food. This appa- 

 rently causes a disease (dysentery) by which they are killed. 

 Or it may be that this wet diet causes more fluid evacuations,, 

 as a result of which the bag becomes soiled inside. The larva 

 then leaves its bag and tries to construct a new dwelling. 

 During this time, when the larvae are unprotected against 

 the inclemency of the weather and against enemies, probably 

 a great many of them perish. Such as survive, in their haste 

 to make a new bag, take any material which comes handy, 

 and old bags, deserted by their inhahitants, are often made 

 use of. In this case we find a great percentage of so-called 

 compound bags, made up of several, sometimes as many as 

 four or five, of which only one is occupied. An abundance of 

 such bags in a plantation is a sure sign that the conditions 

 have been at some time unfavourable to the bagworms. 



In addition to the diseases here enumerated, there are still 

 others of an unknown nature, which attack the older bag- 

 worms. 'I'he effect is a blackening and ultimate mummifica- 

 tion of the larvfe, and many of the older bags which were 

 opened showed evidence of this form of disease. In fact,, 

 these diseases may destroy more bagworms thaii the fungus. 

 We have found amongst several thousands of bag's, collected 

 ill the resting stage, that 30 per cent, of the larvae had been 

 killed olf by these diseases. 



As far as we know, none of these diseases are contagious ; 

 we have found an abundance of perfectly healthy larvge 

 amongst the diseased caterpillars. 



An undoubtedly contagious disease has been noted during* 

 the season of 1918-14. Our attention was first called to it 

 by Mr. H. Holley of Wartburg, who noticed a great 

 number of dead l^agworms in a corner of a plot about forty 



