CONSTITUTION AND DEVELOPMENT OF TERMITES. 89 



as a nest usually contains but a single royal couple, and their 

 interbreeding must therefore vitiate the stock. Swarming 

 brings about the intercourse of examples from different nests, 

 and diminishes the evils of interbreeding by leading to the 

 pairing of non-consanguineous royal forms. This, therefore, 

 is its proper function. 



" In the realisation of this advantage it may too easily 

 happen that the orphaned population is unsuccessful in pro- 

 viding a fresh royal couple for the throne. In this case the 

 royal substitute pairs, or sexually mature nymphs of 

 the second form, step in and thus ensure the safety of 

 the colony. Their slow development is correlated with this 

 function, and their reduction in number during July may 

 possibly indicate that they are killed off when no longer 

 required, and that the colony does not keep alive the large 

 number originally provided. 



'' This hypothesis was supported by the following observation 

 made by Miiller himself in Brazil. He found in the solid core 

 of a Eutermes nest no less than thirty-one substitute queens, 

 which were seen to lay eggs, together with a single true king, 

 possessing wing-stumps ; a true queen was wanting. These 

 supplemental queens bore a general resemblance to workers, 

 but were twice as large; their wing-buds were mostly very 

 short (about half the length of the segment from which they 

 took origin), but were markedly longer in a very few examples. 

 The antennae were fourteen-jointed as in the workers (those 

 of the soldiers having thirteen, of the perfect insects fifteen 

 joints). Their head might be taken for that of a worker, 

 except for the presence of small pigmented compound eyes. 



"These are the whole of the particulars given in Fritz Miiller's 

 paper. Hagen, quoted by Miiller, takes a different view, and 

 believes that all African and Asiatic queens originate from 

 perfect insects, and those in America directly from nymphs. 



" Latterly von Jehring (in Brazil) has published two notes 

 on alternation of generations in Tertnitidse.^ He regards the 

 substitute queens, found on a single occasion by Miiller, and 

 • 'Ent. Nacbr.,' xiii (1887), pp. 1—4, 179—182. 



