274 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 37 



does not reach a maximum "immediately after hatching," but rather 

 at some time considerably past emergence of the adult insect. 



Allen and Richards (1954) have added further evidence for the 

 existence of metachemogenesis in adult Sarcophaga bullata Parker, in 

 the form of variation with age of the enzyme system important in 

 the oxidation of succinic acid (an important metabolic intermediate 



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3 4 5 6 

 AGE- DAYS 



8 



Fig. 7. — Changes in cytochrome oxidase activity with age of male flics. 

 (• resistant strain; ° normal strain.) (After Sacktor, 1950.) 



of the tricarboxylic acid cycle), and the aerobic oxidation of which is 

 effected through the cytochrome system. They found a systematic in- 

 crease in such oxidative activity by homogenates of the thoracic flight 

 muscles, so that it was double by the third day and triple in value by 

 the fifth to sixth day; this was followed by a gradual, slow rise to a 

 maximum on the ninth day. 



