19 



Weinland (1908) observed further that' "bacteria take no 

 part in the process of fat formation in the larvae. 

 Guyenot (1906, 1907) found that muse id larvae (mostly 

 those of Lucilia ) are unable to produce any digestive 

 ferments which liquefy meat. He "believed that this is 

 accomplished by "bacteria. On the other hand, Wollman 

 (1921) claims that aseptically bred larvae liquefy gela- 

 tin, which indicates that they produce some proteolytic 

 ferments . 



One may expect to find almost any saccharolytic enzyme 

 in the digestive tracts of insects if one considers the 

 variety which may arise from the "bacteria they harbor. 

 The fermentative ability of bacteria isolated from the 

 alimentary tracts of insects and ticks varies from almost 

 none to at least 25 or 30 carbohydrates. It is evident 

 that in the insect the bacteria would not be called upon 

 to produce most of these enzymes unless the appropriate 

 substrates were included in the arthropod's food, In 

 the case of the cattle grub, Hypoderma lineatum , Simmons 

 (1939) found the following enzymes to be present: Lactase, 

 maltase, invertase, glycogenase, lipase, trypsin a'nd 

 erepsin. He believed the lactase, maltase, invertase, and 

 renin to be products of bacteria in the intestine of the 

 larva. Brown (1928) believes that most of the enzymes 

 found in the honeybee are produced by microorganisms. 

 It would seem that in most of the studies on the sacchro- 

 lytic enzymes of insects too little attention has been 

 given to the large amounts of these enzymes which bacteria 

 are capable of producing. 



Portier (1911) claims that leaf -mining larvae of 

 Nepticula malella and G-racilaria syringella live under 

 sterile conditions and do not harbor any microorganisms 

 in their bodies. On the other hand, the normal leaf- 

 feeding larva of the silkworm, Bombyx mori, has its 

 digestive tube populated with bacteria, some of which 

 destroy the wall of the leaf cell, while other bacteria 

 thrive on its contents which is used directly as food. 

 G-laser (1925), however, reared large numbers of silkworms 

 and rarely found many bacteria in the digestive system of 

 normal worms. When bacteria became numerically high, the 

 worms ailed and died. Hering (1926) criticizes some of 

 the views of Portier, stating that up to that time no 

 true "symbionts" were known in leaf -miners. Werner (1926) 

 found the digestive tract of the larva of Potosia cuprea 

 to have a very rich microflora able to cause the fermen- 

 tation of cellulose A specific bacterium was isolated 



