53 THE DURATION OF LIFE. [I. 



these insects live as images for six and a half years or 



more \ 



On the other hand, Sir John Lubbock never succeeded in 

 keeping the males ' alive longer than a few weeks.' Both the 

 older and more recent observers agree in stating that female 

 ants, like queen bees, are always protected as completely as 

 possible from injur}^ and danger. Dr. A. Forel, whose thorough 

 knowledge of Swiss ants is well known, whites to me, — 'The 



^ 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 

 3-ears. Cf. ' 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 been published in the Journal of the Linnean Societ}'' 

 (Zoology), vol. XX. p. 133. I quote in full the passage which refers to 

 these ants : — 



' Longevity. — It may be remembered that vay nests have enabled me 

 to keep ants under observation for long periods, and that I have identified 

 workers of Lasius niger and Formica fiisca which w^ere at least seven 

 years old, and two queens of Formica fiisca which have lived with me 

 ever since December 1874. One of these queens, after ailing for some 

 days, died on the 30th 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 oi Formica fusca^\{\Qh. lived to be thirteen years 

 old, and I have now a queen of Lasiiis niger w^hich 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 impossible to estimate their age at the time of capture. It is only 

 certain fas 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 (before their 

 death), but there was no loss of an}^ limb nor an}'- abrasion.' This last 

 observation seems to indicate that queen ants may live for a much longer 

 period in the wild state, for it is stated above that the chitin is often 

 greatly worn, and some of the limbs lost (see pp. 48, 51, and 53'. — 

 E. B. P.] 



