SECT. 7] OF EMBRYONIC DEVELOPMENT 959 



instead of part of the fly; when Tangl's figures were computed in that 

 way, they came to R.Ea. 462 cal. and S.Ea. 1 144 cal., almost in exact 

 correspondence. Tangl next compared these results with those of 

 Farkas on the silkworm's metamorphosis, and found that, though the 

 Ea. of the silkworm was much higher than that of either Ophyra or 

 Calliphora (it is a much bigger insect), its R.Ea. and S.Ea. were very 

 similar: 



calories 



from which he concluded that the energy wasted by combustion in 

 the production of i gm. weight of imago wet or dry from the larval 

 stage was much the same for the two diptera and the lepidopteron. 



The next step in Tangl's calculations was to find out how much 

 energy had to be given off in order to transmute the larva into the 

 pupa. Knowing the weights of the organism at the beginning and 

 end of the pupation period, and having the results of bomb calori- 

 meter measurements at hand, these values were obtained: 



calories 



By adding the results together so that the energy-consumption for 

 the whole period, i.e. from the beginning of pupation to the birth 

 of the adult imago, Tangl got the following figures : 



Ea 



R.Ea 



S.Ea 



which, as he did not fail to notice, are of the same order as those 

 for embryonic development. 



This relation he elaborated at length in the seventh paper of the 

 series. As can be seen from Table 121, where all the relevant data 

 are collected, it was very definitely the case that the period of true 



