SYMBIOSIS BETWEEN TERMITE AND FLAGELLATES. 319 



Leidyopsis, although it is usually never present in nature in 

 nearly such large numbers as Trichotnonas and Streblomastix, is 

 removed the same thing happens to Trichotnonas that happens 

 to Leidyopsis when Trichonympha is removed, namely, Tricho- 

 monas multiplies rapidly and increases very greatly in number 

 for about 30 days, but it never completely fills the intestine of 

 its host. These termites are active for approximately 60-70 

 days on the axerage, but after this period many of them die, 

 although some of them live considerably longer and a very small 

 percentage may be able- to live indefinitely. However, under the 

 present ' OIK lit ions, we may conclude that the symbiosis between 

 Termopsis and its intestinal protozoa is very greatly damaged by 

 tin- removal of Trichonympha and Leidyopsis. Trichotnonas, 

 under these experimental conditions, is undoubtedly of some 

 \ ilue to its host, though certainly not as much as either Tricho- 

 nympha or Leidyopsis. It is able to keep its host alive for at 

 lr.i-t 4> 50 days, for when it is removed, as we shall see in group 

 ;, , the termites die 40-50 days earlier. It is possible that 

 Trichotnonas in this case has to support Streblomastix, as well as 

 its ho-t, for Streblomastix cannot live alone as group f.v r-hows. 

 Streblomasti\ now, as was not the case when only Trichonympha 

 had been removed, increases in numbers considerably, and, if a 

 method for removing it without removing Trichotnonas at the 

 -.urn- time were available, Trichotnonas might then be able to 

 keep pl.t' tiialU all of its hosts alive indefinitely. This, ho\\- 

 ever, being a possibility which has not been toted, more work 

 must be dune before we can speak with exactness upon the 

 precise ability of Trichotnonas to keep its host alive. 



(3) Termites icith Streblomastix. Streblomastix does not in- 

 . rease in number; on the contrary-, it gradually diminishes, and 

 its host dies \\ithin three to four weeks, just as when all protozoa 

 are nnu>\e<l. \Ye conclude, then, that Streblomastix is not a 

 s> inbiont, for it does not seem to be of any value to its host. 

 Incidently, this proto/o.m, unlike the other three genera, does 

 not ingest wood particles from the intestine of its host, which 

 also suggests that it plays no part in digesting food for its host. 

 Streblomastix may depend on the other protozoa for its support. 



(4) Termites icith Trichonympha, Leidyopsis, and Streblo- 

 mastix. These termites are able to live indefinitely and it is 



