44 J. PERCY BAUMBERGER 



covered with Rhizopus nigricans and Penicillium glaucum molds. 

 These growths were turned under each day and the bran thor- 

 oughly wetted till the mash had a sour smell and no longer be- 

 came covered with the molds. Thus far no flies had deposited 

 eggs on the mash, although large numbers of Lucilia caesar and 

 Musca domestica fed on the moist surface. Several lumps of 

 armnonium carbonate were then added, gi^dng the medium an 

 odor indistinguishable from manure. No eggs were observed, 

 but laiTae were soon found feeding just under the slightly in- 

 crusted surface. They gradually worked down in the medium 

 as they became larger and the upper portions of the mash were 

 dried out or the nutritional substances "burned" out by the fungus 

 due to over-aeration. When this same medium was used a 

 second time, larvae were seen to penetrate into hard lumps of the 

 bran which still retained a visible white powdery appearance of 

 fungous mycelia. 



Two-day-old (5-mni.) larvae were transferred to bouillon yeast, 

 banana and yeast, bran and Pasteur's agar media. The larval 

 life was as follows: 



Bouillon agar 5 mm. to pupation 13.5 days 



Pasteur's agar 5 mm. to death 2.0 days 



]iran agar 5 mm. to imago S.O days 



Yeast agar 5 mm. to pupation 4.0 tlays 



Banana and yeast agar o mm. to pupation 4.0 days 



Bran mash 5 mm. to pupation 13 21 .0 days 



The larvae showed signs of great disturbance when placed in the 

 Pasteur's medium where the sugars seemed to act as a poison to 

 them. On bouillon agar the larvae were not very successful in 

 completing growth and usually formed abnormal pupae; on the 

 other agar media growth was more rapid than in the bran mash. 

 This was due to the luxuriant growth of yeast, molds, and bac- 

 teria which the bran, banana and yeast agar supported and which 

 served as food for the larvae. Sections through the larvae from 

 the bran mash showed a complete absence of all material except 

 bacteria, fungous spores, and yeast cells in the digestive tract. 

 The microphotographs in figures 15 and 16 show the process of 

 digestion of the microorganisms and leave no doubt that they 



