62 



Jflll 



I am 



B. H 



erms 



Since there is no appreciable faecal discharge and because the loss 

 is quite gradual, it is assumed to be due to loss of moisture. This 

 loss is less pronounced after the fourth day until the seventh day 

 when pupation takes place. The pupal period is marked by the 

 broken line. Here there is an abrupt loss in weight. During this 

 early period of transformation from larva to pupa the case changes 

 in color from a pale yellow to the characteristic chestnut of the 

 advanced pupa . This change in color, due to the hardening of the 

 chitin, is quite rapid. In the eighth day there is another drop 



450 

 400 



350 

 300 

 250 

 200 

 150 

 100 





o I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 

 Fig. 3 Growth curve of Sarcophaga sarraceniae Riley, derived from Table III, column 4, based on 

 10 individuals; x = days; y = milligrams. The solid line represents the larval period with apex as 

 the point of migration; the broken line represents the pupal period and the drop at the end, the lots of 

 the pupa cases. 



which is followed in the ninth day by a considerable increase. 

 This is also evident in the remaining sets weighed at about this 

 same age. This increase of weight shared by practically all pupae 

 weighed, is probably due to an addition of moisture extracted 

 from the air, or there may be a correlation to internal metabolism. 

 At this point in the life history the metamorphosis is wonderfully 

 rapid. During the first day or two of pupation the individual 



