A NUTRITIONAL STUDY OF INSECTS 69 



there are three stages of putrefaction and a final stage in which 

 the dried tissues are consumed. The first stage of putrefaction is 

 divided into two parts, viz., 'Body still fresh;' fauna consists of 

 Musca domestica, Calliphora, etc.; Tutrid odor develops;' fauna 

 consists of Calhphora, Lucilia, Sarcophaga, etc. The workers 

 of the second stage of putrefaction when butyric fermentation is 

 taking place are Dermestes, Necrobia, Anthomyia, etc. The 

 third stage, the stage of ammoniacal fermentation, is accompanied 

 by infestation with such forms as Silpha, Necrophorus, Hister, 

 Aphyra, Phora, and many Acarina. Finally the dried tissues 

 are consumed by Aglossa, Tinea, Anthrenus, etc., and the bodies 

 of these are destroyed Ptinus. 



As this succession of species in the fauna of dead bodies holds 

 fairly constant, it seems plausible that the odors produced are the 

 determining factor and that the microorganisms producing the 

 odors are of great importance to the insect as food and as solvent 

 agents. Therefore we may conclude that the odors of fermentation 

 and putrefaction are attractive to insects because they indicate 

 a substratum made suitable for the insect by the abundance or 

 the action of microorganisms. 



MICROORGANISMS AS FOOD OF OTHER ANIMALS 



The use of microphytes as food is not confined to insects and 

 mites alone, but is quite common among Protozoa. The effect of 

 pure culture of different species of bacteria on Paramecium has 

 recently been described by Hargitt and Walter ('16). These 

 authors were able to sterilize the animal by six successive wash- 

 ings in sterile water and then raised them on pure cultures of 

 thirty different species of bacteria. They found that the bac- 

 teria from fresh were more favorable than those from older 

 infusions. 



It is probable that many of the Nematoda are also myceto- 

 phags. Anguillula aceti, the vinegar eel, which inhabits the 

 'mother of vinegar' and is also found in sour flour paste, and 

 many of the 'parasitic' nematodes found in decaying plant tissue 

 may be attracted at first by exposed soft tissue and later feed 



