110 ENTOMOLOGICAL SOCIETY 



life of the species, there being no more in this condition than a 

 vita minima, with the reduction of assimilation to its lowest 

 point. 



LONGEVITY IN INSECTS GENERALLY. 



Let us, therefore, glance at the salient facts connected with the 

 longevity of insects, as presented in the temperate zone, consid 

 ering the subject by orders : 



HYMENOPTERA. In the Aculeate section of this order there 

 is seen to be very great irregularity. In almost all the solitary 

 species the term of individual life is limited by the year. This 

 is essentially true of those species which are known to produce 

 but one generation annually, in which case, as in the various 

 species of Anthophora, Melissodes, etc., the hibernating period 

 is usually in the larva state. In species which produce more 

 than one generation annually, the term of life is shortened, espe 

 cially in the imago. Except, however, where the species hiber 

 nates in the larva or pupa state and this adolescent condition is 

 thus prolonged in dormancy or partial dormancy, these solitary 

 members of the Aculeate section undoubtedly live longest in the 

 adult state. 



Among the social species, the subject becomes much more 

 complex, but in most of the social wasps the impregnated females 

 survive the winter, start the colony unaided in the spring, and 

 themselves perish during the latter part of the summer. With 

 the bees, this is also very largely true of most of the genera, but 

 in Apis mellifica, the only species which has been at all care 

 fully studied, the queen is known to live at least three years, 

 though the drones perish either naturally or by violence with the 

 waning summer, and the workers in the height of the season do 

 not average an individual life of more than three months. The 

 maximum life of the worker, including the hibernating season, 

 is about eight months. With the ants there is great variation in 

 the different genera and species, though the great majority resem 

 ble somewhat the social bees in hibernating for the most part as 

 adults. It is well known that the females are longer lived than 

 the workers, though the exact experiments of Lubbock show that 

 these last in some species may live for at least six years, while a 

 queen of Formica fusca which he kept in an artificial formicary 

 attained the age of thirteen years. This is certainly a term of 

 life for an adult insect beyond what we might expect, and even, 

 perhaps, beyond what occurs in nature, since the artificial char 

 acter of Lubbock's nests may have had something to do with the 

 prolongation of the individual life, and on the whole the life of 

 the adult in the Aculeate Hymenoptera, even when we include 



