272 ERNEST AYARREN. 



and the percentage of deaths is sometimes much larger than 

 in the case of maia cited above. 



In this connection a short digression may be allowable. 

 Several years ago some forty full-grown, wild, and apparently 

 healthy caterpillars of Nudaurelia belina were collected 

 and placed in cages with earth. Pupation occurred in a 

 normal manner, but only four moths were ultimately obtained. 

 The majority of the pupte dried up without any appreciable 

 development of the moth. The question as to the actual cause 

 of death requires investigation, but the present point of 

 interest to note is the great natural mortality which occurs^ 

 and therefore the absolute necessity for great reproductive 

 power in the species. 



An analogous case was observed with the so-called Army 

 Worm, which is the caterpillar of a Noctuid, Caradrina 

 e X i g u a. The caterpillar feeds on grasses, but it is moderately 

 omnivorous, and will consume vegetables and other plants. In 

 the middle of May, 1914, a plague of these caterpillars 

 occurred in certain areas of Pietermaritzburg and its environs. 

 From a piece of veld about half a mile from the town 140 

 caterpillars were collected from the grasses. These were 

 mostly full-grown and were on the point of pupating. They 

 were placed in large wooden boxes with a layer of soil at the 

 bottom, and were supplied with food in case some of the 

 caterpillars had not quite finished feeding. Care was taken 

 that the food supplied was dry, as the bad effect of wet food is 

 well known. Ninety-two of the caterpillars died without 

 pupating, and became covered with a whitish mould; the 

 remainder burrowed very superficially into the ground and 

 duly pupated. Of these only nineteen emerged as moths, nine 

 had been stung by a large dipteron parasite, and the remainder 

 (twenty) of the pupa3 dried up. Thus in this case only about 

 13 per cent, of the full-grown larva3 produced moths. 



The only other available Saturniid moth in addition to the 

 specimens of wild maia and bred menippe for use in these 

 breeding experiments were four wild male specimens of 

 Nudaurelia belina caught in Pietermaritzburg. 



