APPENDIX. 51 



however one of the most uncertain in the natural history of ants. 

 On the other hand it is quite certain that the female may live for 

 years within the nest, continuing- to lay fertilized eggs. Old 

 females are sometimes found in the colony, with their jaws worn 

 down to the hypodermis. 



Breeding- experiments confirm these statements. P. Huber l and 

 Christ have already put the life of the female at three to four years, 

 and Sir John Lubbock, who has been lately occupied with the 

 natural history of ants, was able to keep a female worker of Formica 

 sanguined alive for five years ; and he has been kind enough to write 

 and inform me that two females of Formica fusca, which he captured 

 in a wood together with ten workers, in December 1874, are still 

 alive (July 1881), so that these insects live as images for six and a 

 half years or more 2 . 



1 ' Kecherches sur les mceurs des Fourmis indigenes,' Geneve, 1810. 



2 These two female ants were still alive on the 25th of September following Sir 

 John Lubbock's letter, so that they live at least seven years. Of. ' Observations on 

 Ants, Bees, and Wasps,' Part VIII. p. 385 ; Linn. Soc. Journ. Zool., vol. xv. 1881. 



[Sir John Lubbock has kindly given me further information upon the duration of life 

 of these two queen ants. Since the receipt of his letter, the facts have Deen published 

 in the Journal of the Linnean Society (Zoology), vol. xx. p. 133. I quote in full 

 the passage which refers to these ants : 



' LONGEVITY. It may be remembered that my nests have enabled me to keep ants 

 under observation for long periods, and that I have identified workers of Lasius niger 

 and Formica fusca which were at least seven years old, and two queens of Formica 

 fusca which have lived with me ever since December 1874. One of these queens, 

 after ailing for some days, died on the 3oth July, 1887. She must then have been 

 more than thirteen years old. I was at first afraid that the other one might be 

 affected by the death of her companion. She lived, however, until the 8th August, 

 1888, when she must have been nearly fifteen years old, and is therefore by far the 

 oldest insect on record. 



' Moreover, what is very extraordinary, she continued to lay fertile eggs. This 

 remarkable fact is most interesting from a physiological point of view. Fertilization 

 took place in 1874 at the latest. There has been no male in the nest since then, 

 and, moreover, it is, I believe, well established that queen ants and queen bees are 

 fertilized once for all. Hence the spermatozoa of 1874 must have retained their life 

 and energy for thirteen years, a fact, I believe, unparalleled in physiology.' 

 ******* 



' I had another queen of Formica fusca which lived to be thirteen years old, and 

 I have now a queen of Lasius niger which is more than nine years old, and still lays 

 fertile eggs, which produce female ants.' 



Both the above-mentioned queens may have been considerably older, for it is im- 

 possible to estimate their age at the time of capture. It is only certain (as Sir John 

 Lubbock informs me in his letter) that ' they must have been at least nine months 

 old (when captured), as the eggs of F. fusca are laid in March or early in April.' 

 The queens became gradually ' somewhat lethargic and stiff in their movements 



E 2 



