334 



FRANCIS O. HOLMES. 



one of the objects of the histological examination of the insects 

 was accomplished. 



It was interesting to note that the flagellates always developed 

 in the dorsal lobe most abundantly. A few penetrated the 

 anterior, but none the ventral lobe. Evidently the differences 

 in the compositions of the salivary secretions of the three lobes, 

 indicated at once by the different staining reactions of the three 

 portions, had also a significant effect on the organisms, inducing 

 them to inhabit one portion more than others, and excluding 

 them from the ventral lobe. 



FIG. 5. A portion of the wall of the dorsal lobe of the salivary gland of an 

 infected Oncopeltus. The nuclei of the gland cells are gigantic in comparison 

 with the minute nuclei of the flagellates. 



In my material no intestinal forms were found. This is 

 remarkable when one considers that the type species of the 

 genus Herpetomonas is a- strictly intestinal flagellate in the 

 common housefly. Salivary gland forms are the exception rather 

 than the rule among Herpetomonads, and it would be expected 

 that intestinal forms of the flagellate would be more noticeable 

 than the gland forms. But if the flagellates of Oncopeltus 

 fasciatus (Dall.) ever show intestinal forms I have not been able 

 to secure the proper material to demonstrate them. 



In addition to the complete series of sections of three individ- 

 uals of Oncopeltus fasciatus (Dall.), a group of ten of the same 

 species was sectioned and studied by choosing representative 

 sections for staining and for examination. Sixteen individuals of 

 Lygceus kalmii from Massachusetts were treated in the same way. 



