322 L. R. CLKVKI.AND. 



present in most of the material used. The two species probably 

 harbor an identical protozoan fauna. 



Four genera of protozoa are invariably present in these ter- 

 mites. These in order of size are: Trichonympha (Fig. i), 

 Leidyopsis (Fig. 2), Trichomonas (Figs. 5, 6), and Streblomastix 

 (Fig. 4). Kofoid and Swezy ('19) claim that another genus, 

 Trichomitus (Fig. 3), is also present, but, for reasons given in 

 this paper, it is impossible to say whether or not Trichomitus is 

 present. If it is, it reacted in every way as Trichomonas did, 

 and has the same relation to its host and fellow protozoa as 

 Trichomonas. 



Two methods, starvation and oxygenation, for removing the 

 protozoa are given. By using each method separately and by a 

 combination of the two it was possible to get five different com- 

 binations of the protozoa, without injuring the termites in the 

 least. By starving for 6 days, Trichonympha was removed 

 entirely; by starving for 8 days, Leidyopsis was removed com- 

 pletely; by oxygenating for 25 hours, Trichomonas was entirely 

 removed; by oxygenating for 24 hours and starving for 6 days, 

 Trichomonas and Trichonympha were removed; by oxygenating 

 for 24 hours and starving for 8 days, Trichomonas, Trichonympha 

 and Leidyopsis were removed; by oxygenating for 72 hours, all 

 protozoa were removed. From this we get one group of termites 

 with no protozoa in them and five groups with a different com- 

 bination of protozoa in each group as follows: (i) Leidyopsis, 

 Trichomonas, Streblomastix; (2) Trichomonas, Streblomastix; (3) 

 Streblomastix; (4) Trichonympha, Leidyopsis, Streblomastix; (5) 

 Leidyopsis, Streblomastix; and (6) no protozoa. By feeding the 

 normal diet of wood to each of these groups of termites it was 

 possible to work out the relation of each protozoan genus to its 

 host and to its neighbors or fellow protozoa. 



When group (i), which contained Leidyopsis, Trichomonas and 

 Streblomastix, was fed wood, Leidyopsis multiplied rapidly, in- 

 creased greatly in number and was able in 20-30 days to fill the 

 vacant space made in the host's intestine when Trichonympha 

 was removed. This group is able to live indefinitely. 



When group (2), which contained Trichomonas and Streblo- 

 mastix, was fed wood, Trichomonas, like Leidyopsis in group (i), 

 multiplied rapidly and increased greatly in number for about 30 



