GENUS: CYSTOTRYPANOSOMA 373 



choidomonas (see below) type of Patton were also found. According to 

 Roubaud, it has been the custom to include in the genus Trypanosoma 

 the typical forms parasitic in the blood of vertebrates, and those which 

 are purely insect flagellates. The latter produce cysts, as noted above, 

 while the former do not. Accordingly, he proposes to divide the genus 

 Trypanosoma into two sub-genera: Trypanosoma for the blood parasites 



' .f ." #" ^^ «^ 



Fig. 173. — Trypanosoma (jrayi in Intestine of Glossina 2)alpalis (x 2,000). 

 (After Minchin, 1908.) 



1-7. Division of typical crithidia forms. 8. Trypanosome form. 



9-16. Stages in the supposed formation of the cyst. 



of vertebrates, and Cystotrypanosoma for the cyst-producing forms of 

 invertebrates. Another flagellate, which Roubaud includes in the latter 

 genus, is Herpetomonas grayi Novy, 1906 (called by Novy, Minchin, and 

 others Trypanosoma grayi, and by Roubaud Crithidia grayi). This organism 

 (Fig. 173) occurs in the digestive tract of Glossina palpalis, G. brevipalpis, 



