Lygaeidae which, she says, undoubtedly carry "bacteria in 

 their cecal appendages. She found the ceca to "be as well 

 filled with "bacteria after the long period of winter rest 

 as they were during the active summer season. Kuskop 

 "believes the "bacteria play a symbiotic role in "being 

 essential in the physiology of the insect's digestion. 



Fate of Bacteria During Metamorphos is . The fate of the 

 "bacteria harbored "by the larva during the process of 

 metamorphosis to the adult stage has not "been studied 

 thoroughly. Such knowledge would "be particularly valuable 

 from the standpoint of public health. For example, house- 

 fly larvae may "become a reservoir for "bacteria pathogenic 

 to man. Should these "bacteria survive metamorphosis and 

 "be disseminated "by the adult, the chances of spreading 

 disease are great. Also, in deciding what is the normal 

 flora of an adult insect, one would have to consider 

 adventitious "bacteria that have "been acquired not only "by 

 the imago itself, hut "by the larva as well. 



Bacot (1911) found that pupae and imagines of Musca 

 domestica "bred from larvae infected with Pseudomonas 

 aeruginosa under conditions which excluded the chance of 

 re -infection in the pupal or imaginal period, remained 

 infected with the "bacterium. Other authorities, however, 

 are agreed that such non- spore -forming organisms as 

 Eberthella typhosa , Salmonella enteritidis and Shigella 

 dysenteriae added to the food of fly larvae usually do 

 not survive metamorphosis (Graham-Smith, 1913)- Later, 

 Bacot (191*0 studied the "bacteria of the alimentary canal 

 of the flea during its metamorphosis and found that the 

 alimentary canal of the flea larva may "become "infected" 

 with the following "bacteria if they are mixed with its 

 food: Pseudomonas aeruginosa , Salmonella enteritidis , 

 Staphylococcus aureus, and S. albus . These organisms may 

 persist in the larval gut until the resting period of the 

 larva in the cocoon, "but there appears to "be no satis- 

 factory evidence that they can survive the pupal stage. 



An interesting example of the survival of "bacteria 

 in an insect during metamorphosis has "been shown "by 

 the work of Leach (1931, 1933) in the case of the "bacter- 

 ium causing potato "blackleg, Erwinia carotovora , and 

 the seed corn maggot, Hylemyia c ill crura . The maggots 

 pick up .the "bacteria from their contaminated egg shells, 

 from the soil, and prohahly from the surface of con- 

 taminated potato seed pieces. After 2 or 3 weeks' 



