80UTH AFRICAN BAGWORMS. 673 



■segment ; segments 6 to 8 unarmed. All of the segments 

 2-7 each show a dark puncture dorsad of the spiracle. 



Abdominal segments 1 to 6 strongly striated transversel}^ 

 ■on their dorsal aspect ; ventral aspect, as also the whole of 

 segment 8, practically smooth. Last segment with a minute 

 hook ventrally situated and directed cephalo-ventrad (i). 



Duration of the pup a- stage. — Individual records of 

 the length of the pupa stage are not available, owing to the 

 practical difficulty in rearing the adult after repeated dis- 

 turbance of the larva in the prepupal stage or the pupa itself ; 

 but from a comparison between the pupation curve and emer- 

 gence curve in text-fig. 4 we can readily deduce the average 

 duration of the pupal period. These curves aT*e based upon 

 the examination of one thousand bags collected in a certain 

 block every week, weather permitting, from April 9th until 

 September 10th, some twenty thousand bags in all. From 

 these curves we see that the males began to pupate during 

 the first week in April, the number of male pupa? per 

 thousand bags rapidly increasing, until at the end of the 

 month a maximum was reached, showing that the male larva? 

 had completed their pupation. This percentage remained 

 practically stationary, allowing for slight variations in the 

 various lots, until the middle of June, after which, some 

 isolated males began to appear. The maximum emergence of 

 males, shown by the empty pupa-cases, was reached on 

 August 16th, the main emergence starting about the middle 

 of June. Therefore, taking as an average the period from 

 the middle of the pupation curve, Api'il 17th, to the middle 

 of the emergence curve, July 31st, we find for the duration 

 of the pupa stage the average of three months and thii'teen 

 days. 



The females did not start to pupate until about a month 

 after the males, the first female pupae having been observed 

 on May 10th ; the maximum, showing that practically all had 

 pupated, occurred about the middle of June. Shortly after- 

 wards the first female adults were found. The general emer- 

 gence, if it may be so called, started about the middle of 



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