20 



J. PERCY BAUMBERGER 



As Agaricus campestris has a protein content of 3.5 per cent as 

 compared with the 1 per cent protein content of banana, this fungus 

 was used as a food for larvae. Drosophila females oviposited read- 

 ily on a medium of powdered Agaricus campestris, water, and agar. 

 The sterile larvae grew rapidly to a size of 6 mm. (the maximum 

 size on yeast is 8 mm.) and pupated after an average of 12.43 days. 

 The curves of growth are shown in figure 6 and a typical record 

 in tables 4 and 5. The adults that emerged from these pupae were 

 sexually fertile, but w^ere quite small. A generation of larvae reared 

 from some of these adults grew more slowly than normal on 4 per 



^1 3M 4 *) 7| e| 



i\r 



4ge 



Uot/^. 



P =■ Pupation. 



D -= Deo//> of /arf,7 



iz l|3 l|4 \i l|«, l|7 l|a l|9 2|o 2]l i|i Afi B\4 j|S I:|6 2|7 i]6 



Fig. 5 Larval growth on banana. 1, mashed whole banana infected with 

 living yeast; 2, 3, 4, sterile mashed whole banana; 5, 6, hot aqueous extract of 

 banana; 7, cold aqueous extract of banana. 



cent yeast, requiring thirteen days instead of seven days to reach 

 maturity (fig. 6, curve 2, and table 5). Sexually fertile adults 

 can be reared from larvae fed on mushrooms, but such adults are 

 undersized. Agaricus campestris meets more nearly the food 

 requirement of larvae than banana; this may be due to the higher 

 percentage protein content of the mushroom or to a relatively 

 higher content of certain necessary amino-acids. 



/. Is yeast a more adequate food than fruit because of its high 

 protein content? The slow growth and small size of larvae and 

 their failure to pupate when reared on sterile fruit are typical 



