tion of the m. n. c. in the young fly gave the result that the development 

 of the ovaries, and the growth of the с all., the accessory glands and the oeno- 

 cytes was arrested. Implantation experiments showed this effect of the т.п. 

 с to be hormonal. 



Table 1 



Proteinase activity per midgut of 7 — 9 hours old females and of sugarflies, normal 

 (unoperated) controls, and females deprived of medial neurosecretory cells. Five days old at 25°C. 



It has been known for many years that Calliphora can live on sugar and 

 water alone, but in order to be able to develop its eggs the fly has to eat 

 meat, and some years ago it was shown that also the growth of the corpus 

 allatum, the accessory glands and the oenocytes is dependent on the intake 

 of protein. In sugar-flies, i. e. flies fed on sugar and water only, but no meat, 

 the organs just mentioned develop to a certain degree on the protein present 

 in the pupal fat-body which persists the first 3 to 4 days of the imaginai 

 stage, but this development is very slight when compared with that of flies 

 fed on meat also. 



A comparison of the ovaries and the other organs of flies deprived of their 

 m. n. с with those of sugarflies showed that they were very nearly the same 



122 



