Ill] 



OF CERTAIN INSECTS 



163 



second. Before entering on the pupal or chrysalis stage, when the 

 worm is about seven weeks old, a remarkable process of purgation 



10 



15 



20 



25 



30 



35 



40 

 days 



Fig. 35. Growth in weight of silkworm. From Ostwald, after Luciani 

 and Lo Monaco. 



takes place, with a sudden loss of water, and of weight, which 

 becomes the most marked feature of the curve* That the meta- 



* Luciani e Lo Monaco, Arch. Ital. de Biologie, xxvii, p. 340, 1897; see also 

 Z. Kuwana, Statistics of the body-weight of the silkworm, Japan. Journ. Zool. 

 VII, pp. 311-346, 1937. Westwood, in 1838, quoted similar data from Count 

 Dandolo: according to whom 100 silkworms weigh on hatching 1 grain; after 

 the first four moults, 15^ 94, 270 and 1085 grains; and 9500 grains when full-grown. 



