INTESTINAL PROTOZOA OF TERMITES. IQ9 



were used in these experiments and, in every case, death occurred, 

 as in the preliminary experiments, within 10-20 days on the aver- 

 age after incubation. In no case did the unincubated and faun- 

 ated controls die. In fact, they are still alive now, more than six 

 months since many of the experiments were completed. 



How may the cause of the incubated and defaunated (with 

 the protozoan fauna removed) termites' death be determined? 

 Is death a direct resit of the incubation? That is, if the termites 

 did not harbor intestinal protozoa which are killed off by the 

 incubation, would death result in 10-20 days? In other words, 

 is the death of the protozoa harbored by the termite in any way 

 connected with or responsible for the death of their host; or is it 

 an entirely independent phenomenon having nothing at all to 

 do with the termite's death. In an effort to answer these ques- 

 tions many experiments were carried out, but only those experi- 

 ments whose results throw some light on the questions involved 

 will be mentioned and discussed. 



Insects, like the cockroach, rather closely related to the ter- 

 mites morphologically, and many wood-boring beetles, rather 

 closely related to termites in habits, were incubated at the same 

 temperature for the same length of time, and for a longer time, 

 as were the termites. These were carefully observed for two 

 months after incubation and no abnormalities were ever observed 

 in any of them. It seems, then, that this temperature is not 

 detrimental to these insects. But the fact that a cockroach or a 

 wood-boring beetle is not killed by the incubation method em- 

 ployed in killing the protozoa of termites, does not show that the 

 termites themselves were not killed directly by incubation, 

 because these insects do not harbor a vast multitude of intestinal 

 protozoa that are suddenly killed off, as do the termites; and 

 besides, they are, after all, quite different in some respects from 

 termites. 



Nasuliternies morio Latreille, from Porto Rico, one of the Ter- 

 mitida-, and, of course, a termite which does not harbor intestinal 

 protozoa, was procured for experimental purposes, the idea being 

 tli.it if this termite could withstand the same incubation tempera- 

 ture that Reticiilitermes flavipes had been subjected to, and re- 

 crive no ill effects therefrom, as evidenced by its ability to live 

 indefinitely after incubation, the probability that Reticiilitermes 



