GROWTH IN TIME OF THE TOTAL ORGANISM 



197 



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■ ► 17 



Fig. 16. Weight growth in Blatta orientalis in semilogarithmic plot. The subsequent 

 meltings {M^-^ M^, M^ -^ M^, M^ —>■ M-j, Mj -^ A = adult) are juxtaposed showing that 

 each cycle consists of 3 phases (rapid, less rapid exponential growth, and loss of weight in 

 molting). The parallelism of the lines for each cycle shows the general exponential type of 



growth. After Voy, 1951. 



insect larvae, metamorphosis abruptly intercepts the exponential increase, even 

 causing a loss in body weight as large amounts of tissue are broken down in order 

 to develop the imago. The same metabolic and growth type also applies to 

 hemimetabolic insects (Table 8, Figs. 16, 17) where no metamorphosis occurs. 

 This at first glance appears perplexing but is in fact what is to be expected because 

 there seems to be no fundamental difTerence between holometabolic and hemimeta- 

 bolic insects in the basic developmental processes and hormonal mechanisms. 

 In land snails which also belong to this type, exponential growth appears to be 

 intercepted by seasonal cycles. 



Literature p. 253 



