142 HUGH GLASGOW. 



parasitic bacteria and protozoa in the alimentary canal. This 

 relation is especially marked in those insects feeding normally 

 on solid materials which may be more or less contaminated in 

 the beginning, but it also applies to sucking insects which feed 

 normally on sterile liquids, although such insects are usually less 

 heavily infected. Mosquitoes and other blood-sucking insects 

 are excellent examples of this, for while they feed largely on the 

 normally sterile blood of vertebrates they usually contain a great 

 variety of bacteria and flagellate parasites in the stomach and 

 intestine, which clearly have no relation to the vertebrate from 

 which the food was secured. 



Early in the work a peculiar infection was observed in Peri- 

 balus limbolarius, a pentatomid in which the creca are well 

 developed. In the specimens of this species, collected from 

 certain localities, fully ten per cent, of the individuals showed an 

 extremely heavy infection of the large sac-like reservoirs of the 

 salivary glands (Plate II., Fig. 4) with a flagellate of the Herpeto- 

 monas group. This organism was apparently going through a 

 normal developmental cycle in these organs, as all stages could 

 be readily observed, ranging from minute, rounded or pear- 

 shaped, non-motile bodies, with a distinct nucleus and blepharo- 

 plast, but with no flagellum, to the long, slender, typical Herpeto- 

 monas stage. Multiplication rosettes were also abundant, 

 showing that the organism had evidently fully established itself 

 in these organs. Infection with organisms very similar to the 

 species found in Peribalus have been observed and described 

 in connection with a very large number of different insects, 

 including especially many Diptera and predaceous Heteroptera, 

 but so far as I have been able to discover, these infections have 

 been confined to the stomach and intestine and are never known 

 to be localized in the salivary glands. 



In working up the development of the Herpetomonas from 

 Peribalus, the alimentary canal was searched very carefully 

 in a large number of individuals, as it was thought that the 

 organism observed in the salivary glands probably represented 

 the final stage in the life history of some intestinal form; but 

 although a very thorough search was made, not the slightest 

 indication was found of an invasion of the midintestine by this 



