CONSTITUTION AND DEVELOPMENT OP TERMITES. 13 



specimens, in which the generative glands are still 

 very immature, or before they are in a condition to 

 undergo compression by the caecal ampulla, suggests 

 that the absence of Protozoa may not be unconnected 

 with the maturation of the glands. 



The experiments and observations described below were 

 undertaken by me in order to determine better the importance 

 of these parasites. 



D. Experiments and Observations on Nests kept in 



Glass Tubes. 



{a) Calotermes. 



1. Numerous small nests were made in glass tubes, each 

 containing from fifteen to forty examples of different ages, but 

 no adults and no royal pair.^ After a few days from two to 

 six incipient substitute forms, characterised by the pigmented 

 eyes, were found in each tube ; they were usually obtainable 

 in about a week if the tubes were carried in the waistcoat 

 pocket, and in summer they often appeared as soon as the 

 fourth day. In fact, after as short a time as thirty or forty 

 hours one could tell which individuals were capable of acquir- 

 ing the ocular pigment. 



The abdomen of these specimens presents a characteristic 

 appearance, being hyaline and destitute of the tinge of colour 

 caused by the food (wood). They evidently possess no Protozoa. 

 But those which assume this appearance do not always acquire 

 the ocular pigment, — that is, they do not always become royal 

 substitute larvae. The eyes become (invariably ?) pigmented 

 without an antecedent ecdysis. 



The formation of such incipient royal substitutes never 

 takes place in any tube containing a royal pair. But if the 

 king and queen are removed for twenty-four or forty- eight 

 hours, or are injured, a few substitute forms appear at times. 



1 The wood ia such nests should not be white, or the presence or absence 

 of Protozoa cannot be readily distinguished by examination of the specimens 

 with the naked eye or a simple lens. 



