3OO L. R. CLEVELAND. 



in which case the protozoa die due to wood starvation, just as 

 happens experimentally (Cleveland, '256) when any normal wood- 

 feeding termite containing a large number of protozoa is starved. 

 In all three reproductive castes it is quite evident that much less 

 wood is eaten at this time; but in the first form the wood diet 

 is not entirely given up; it may be curbed greatly, though never 

 supplanted, by the salivary diet. It is interesting in this connec- 

 tion to note that the first forms eat much more wood shortly 

 after the final molt and, because of this, the protozoa increase 

 rapidly in number. They certainly receive no salivary secretion 

 from workers for sometime if they leave (swarm) the parent 

 colony to start a new colony, and nearly every one, if not every 

 one, leaves or is killed. Their only food is wood until they rear 

 workers to furnish them salivary secretions again, and when 

 this is done, they again progressively cease to eat w r ood, finally 

 giving up the habit entirely, at which time they lose all their 

 protozoa and become dependent on the xylophagous members of 

 the colony for the rest of their lives. It is interesting here to 

 note that instinctively this dependence, which is perhaps in- 

 evitable, is well taken care of or looked forward to, because 

 mostly workers are reared in the first brood of such a reproductive 

 pair. But would they become dependent if not allowed to rear 

 workers, that is if the larvae were killed or taken from them? 



We have already said that one reason why the second and third 

 form young adults die when placed by themselves is because they 

 lose their protozoa, and the protozoa are lost because these 

 forms do not feed on wood, the second and perhaps more funda- 

 mental reason why death results when such individuals are 

 isolated. But w r hy do they not eat wood? According to Thomp- 

 son and Snyder ('20) the jaw muscles and many others, particu- 

 larly those in the head, of the first form degenerate during the 

 post-adult stage. "This degeneration of the jaw muscles," they 

 state, "is due to the fact that the reproductive forms are now 

 fed by the workers on partly digested food and no longer masti- 

 cate wood as they were compelled to do before the first broods 

 of workers were raised." These authors also observed that the 

 jaw muscles in the second and third forms in the post-adult 

 stage had degenerated, though they did not state when the 

 degeneration occurred. If, in the first forms, it occurs, as they 



