A NUTRITIONAL STUDY OF INSECTS 



27 



is only a variation of 0.76 day and between 3 per cent and 24 

 per cent — a difference of 1.11 days. It appears that the normal 

 condition for larval growth is in a medium of yeast concentration 

 between 6 to 24 grams per 100 cc. This is shown in the size of 

 pupae in table 8. 



□ =■ Lori^a/ fier/oa'. 

 0= Pupa/ Penoc/ 



C<y/JCCn/r£r//'7/p 17/ h^^rj-/ //? ^^c 



'I A =\ "I ^1 e| 'I «l ^1 



rr ,2 to It 



-iFli- 



TTT^ 



Fig. 8 The effect of the concentration of yeast on the length of the larval and 

 pupal periods. 



A concentration of 1 per cent of yeast appears* to be sufficient 

 to furnish the energy, repair, and some growth requirements of 

 the larvae for a considerable period without furnishing quite 

 enough food to allow the necessary growth changes or storage 

 preliminary to pupation. The larval period must be considered 

 as a nutrition unit. In the case of larvae on 2 per cent yeast, 

 the insect obtains in 11.4 days sufficient food material to give 



