ISOPTERA 



277 



-A sol- 



tennes and Cryptotermes, where the nymphs of the reproductive forms 

 apparently attend to the duties of workers; and in the genera 

 Termopsis and Neotermes ordinary sterile workers are not found, but 

 the third reproductive caste, large, worker-like, grayish brown, fertile 

 forms, with no wing-buds, is present. The nymphs of this caste often 

 perform the duties of the workers (Banks and Snyder '20). In some 

 tropical species there are two types of workers, which 

 differ in size. 



The soldiers. — ^Associated with the workers, and 

 resembling them in color and in being wingless, there 

 occur numerous representatives of another caste, 

 which can be recognized by the enoimous size of their 

 heads and mandibles (Fig. 313); these are the sol- 

 diers. They are so named because it is believed that 

 their chief "function is the protection of the colony; 

 but they do not seem to be very effective in this. 

 Among the soldiers, as among the workers, both sexes 

 are represented ; but as a rule the reproductive organs 

 are not functional. Sometimes, however, soldiers 

 capable of laying eggs are found. In the genus Fig-. 3i3- 

 Kalotermes soldiers with small wing-buds are often ^^'^^• 

 foimd. The soldier caste has not been ioxm&mthe germs, Anoplotenncs, 

 and in the genera Constrictotermes and Nasutitermes the soldier caste 

 is wanting unless the nasuti, described in the next paragraph, are 

 regarded as soldiers. In certain tropical species there 

 are two types of soldiers which differ in size. 



The nasuti. — In certain species of termites there 



are found individuals in which the head is elongated 



into a nose-like process, from the tip of which a fluid 



^, exudes, which is used as a means of defense and also, 



1^^^ it is said, as a cement in constructing the nest and 

 y^^^ the earth-like tubes through which the insects travel 



(Fig. 314). Such individuals are known as nasuti. 

 In this caste the mandibles are small, differing greatly 

 from those of soldiers . The nasuti are usually smaller 

 than the workers and are pigmented. They have 

 been commonly described as a special type of soldiers ; 

 but it seems better, in order to avoid confusion, to 

 regard them as constituting a distinct caste. Among 

 the North American termites, nasuti are found in 

 the genera Constrictotermes and Nasutitermes, which 

 lack the true soldier caste. In some tropical termites two types of 

 nasuti, large and small, have been found. 



As to the origin of the different castes of termites there has been 

 much discussion and two radically different views are held. The 

 first view was probably suggested by the well-known fact that, in the 

 case of the honey-bee, queens can be developed from eggs or young 

 larvcE that ordinarily would produce workers. According to this view 

 the newly hatched termites are not differentiated into castes; but 



Fig. 314. — A nas- 

 utus. (Aftei 

 Sharp.) 



