REVISION OF NEARCTIC TERMITES. Ill 



Soldier termites are more highly specialized workers, being also 

 developed from large-headed worker-like nymphs that will not nor- 

 mally mature the sexual organs, and the caste is represented by both 

 sexes. While they are soft-bodied, the head, which is pigmented, 

 is chitinized. The mandibles are enormously developed in some 

 species; there is, of course, great generic variation in the size and 

 shape of the head and mandibles of the soldiers. The soldiers are 

 usually larger than the workers. In the genus Termopsis there is a 

 great variation in the size of the soldiers ; soldiers of species of Kalo- 

 termes also vary in size. 



In the genera Constrictotermes and Nasutitermes there is no mandib- 

 ulate soldier caste present, but there is a striking form with a nose- 

 like process, beak, or nasutus — the "nasutus" caste. Liquid is 

 exuded from this beak as a means of defense. The nasuti are 

 usually smaller than the workers, are pigmented, and in the foraging 

 species have long legs. Nasuti are usually constant in size. 



In the genus Anoplotermes there is no soldier caste. 



The soldiers, more highly specialized workers, are of less importance 

 functionally than the workers — just as the anther transformed to 

 the petal in the common pond lily (Castalia, species) is less important 

 functionally than the other anthers — yet both serve a purpose. 

 Just before the time of swarming the members of colonies become 

 restless, and as the sexual adults emerge numerous workers and 

 soldiers congregate on the outskirts of the colony near the exit holes 

 with heads toward the exterior. The duty of the soldiers is appar- 

 ently entirely protective, but they do not appear to be very effective, 

 at least when the colony is opened and they are exposed to the attack 

 of ants, etc. 



''Tropliallaxis." — In connection with the outline of the workers' 

 and soldiers' duties in the colony life, the following explanation is 

 offered : 



The colony life of the so-called "social insects" — that is, the ants, 

 termites, bees, and wasps — ^has always excited interest. The care 

 of the brood and the queen by the workers and the alarm manifested 

 by the workers and soldiers of termites when the colony is broken 

 into and the brood or queen are disturbed have called forth praise. 

 In these prosaic days of biological /acis much of the mystery of the 

 complex social system of the ants and termites which led to admira- 

 tion by man has had to "go by the board." Many fantastic theories 

 have collapsed. 



One of the first of these theories to go was the instinct for the care 

 of the brood and queen.. Nils Holmgren (1909), in his studies of 

 the anatomy of termites, devotes considerable space to the exudate 

 tissues. All of the castes, but especially the queens, have extensive 

 exudate tissues in the abdomen. This exudate passes through 

 pores in the chitin to the surface. Here it is greedily licked up by 



