58 HAROLD HEATH. 



believe that they have existed for five years at least. There is 

 not the slightest evidence that the kings do not live as long as 

 the queens. After the death of the royal pair from natural or 

 other causes the members of the orphaned colony (to use Grassi's 

 expressive term) develop a number of substitute royal forms. 

 The individuals chosen for this purpose are usually the larvae of 

 perfect insects in which the wing buds are barely visible. By 

 some unknown process, possibly by a peculiar method of feeding 

 or some change in their diet, the external larval characters are 

 retained (the larvae undergoing no subsequent molts), while the 

 reproductive organs are stimulated to active growth culminating 

 in full functional activity. Very shortly, often within a month 

 after the death of the primary pair, these substitute forms may 

 be detected, owing to their faint straw color, which rapidly grows 

 to a very much darker tint during another month. 



If only one of the royal pair be destroyed usually only one 

 substitute form is developed, but when both perish from ten to 

 forty substitutes appear, according to the size of the colony. In 

 two nests carefully examined I found six substitute males and 

 eleven females in one, and nine males and thirteen females in the 

 other. As might be expected, these do not mate permanently, 

 and one male may pair with three or four queens during the 

 course of an hour. 



The substitute individuals are fed and cleaned almost entirely 

 by the workers, which also assume the care of the young. Ac- 

 cordingly the royal task consists almost altogether of egg-laying 

 and is performed with comparative rapidity. Some of the larger 

 queens (Fig. 2) lay continuously from seven to a dozen eggs in 

 twenty-four hours and where several are associated together the 

 colony rapidly assumes large proportions. In the extensive nest 

 of Tennopsis mentioned on page 48 there were over thirty substi- 

 tute individuals which were congregated beneath a small strip of 

 bark where the sun shone brightly, and with them was a clump of 

 eggs, attended by many workers, that I carefully estimated at not 

 less than 8,000. 



In colonies where either the king or queen persists the substitute 

 royal individual is invariably, so far as I know, an immature per- 

 fect insect, but where both have perished the substitute royalty 



