272 RESEARCH IN PROTOZOOLOGY 



The full life cycles in insects are not known in most cases. 

 Herpetomonas davidi has been traced through SfeiiocepJialiis agilis 

 by Franga. It is still a question whether latex flagellates are in- 

 tracellular at any stage in the insect hosts. 



Flagellates show abnormal methods of division in hosts not 

 normal to them. Thus Herpetomonas elmassiani in Lygceus kalmii 

 forms small bud-like aflagellate cells at the anterior end of the 

 organism, clustering around the flagellum. These have been ob- 

 served in the living condition. When stained such forms each show 

 a nucleus and a parabasal body, but no new flagellum. They are 

 very short, and are present to the number of two or three or 

 more at the anterior end of the parent cell. It would be desirable 

 to know what their nature and function are. 



Degree of specificity for plant hosts. Latex flagellates are not 

 specific for individual species of plants. By means of Oncopeltus 

 fasciatiis the writer has transmitted Herpetomonas elmassiani to 

 several Asclepias species, A. nivea, A. curassavica, A. pulchra, 

 and A. incarnata, and from all reports the flagellate may be trans- 

 mitted to any species of the family asclepiadace^. The range of 

 Herpetomonas davidi is considered to be very wide, but only field 

 observations are available. A list of Euphorbia species in which 

 this flagellate has been found is given by Gaschen (1926), and 

 by Wenyon (1926). 



Possible presence of protozoa in commercial latex plants. Since 

 most of the commercially valuable species of latex plants are 

 cultivated in warm climates where insects with flagellate infections 

 are abundant, it is probable that flagellates will be found in some 

 cases when adequate search is made. Such search has not yet been 

 made in commercial plantings of figs or rubber trees. It is probable 

 that the now extensive plantations will eventually attract hemip- 

 TERA capable of feeding upon the cultivated species. These hemip- 

 TERA may then introduce protozoa formerly confined to small 

 numbers of wild plants in the neighborhood. 



Preliminary statements by Fantham in South Africa and Ban- 

 croft in Queensland mention latex flagellates in Ficus species {F. 

 edulis and F. scabra). It is not yet known whether the organisms 

 are harmful to the hosts. In commercial rubber plants no flagellates 

 have been reported, and in other latex plants no statements have 

 been published as to the effect of the presence of the flagellates 

 on the rubber content of the plants. 



