50 SIB JOHH- LTTBBOOK ON AFTS, BEES, AND WASPS. 



of my nests of Formica fusca was brought from tte woods in 

 December 1874 ; it tben contained two queens, both of which 

 are now still alive. I am disposed to think that some of the 

 workers now in the nest were among those originally captured, 

 the mortality after the iirst few weeks having been but small. 

 This, of course, I cannot prove. The queens, however, are cer- 

 tainly more than eight, and probably now more than nine years 

 old. In the nest of Lasius niger which I brought in on the 30th 

 November 1875 there was no queen, and, as already mentioned, 

 no workers have been produced. These two still living are 

 therefore the original ones ; and they must be between seven and 

 eight years old *. 



I had also some workers of Lasius niger which I began to 

 observe on the 6th July 1875 ; the last of these died on June 15th, 

 1881. 



Lastly, some of Formica cinerea, which I began to observe on 

 the 29th November 1875, lived till the ants in this nest died off 

 somewhat rapidly, the last on July 23, 1881. There were no 

 queens in either of these nests ; these workers therefore must 

 have been more than six years old. The workers of Lasivs niger 

 above mentioned, which were born at latest in the spring of 1875, 

 must now be more than seven, and my two queens of F. fusea 

 more than eight years old. 



Sensitiveness of Ants to the Ultra-violet Bays. — Mr. Wigner (of 

 Messrs. Harland and Wigner) was good enougli to prepare me 

 •a solution of iodine in bisulphide of carbon, and a second of 

 indigo, carmine, and roseine mixed so as to produce the same tint. 

 To our eyes the two were identical both in color and capacity ; 

 but of course the ultra-violet rays were cut off by the bisulphide- 

 of-carbon solution, while they were, at least for the most part, 

 transmitted by the other. I placed equal amounts in flat-sided glass 

 bottles, so as to have the same depth of each liquid. I then laid 

 them as in previous experiments over a nest of Formica fusca. 

 In twenty observations the ants went seventeen times all under 

 the iodine and bisulphide, twice under the solution of indigo and 

 carmine, and once there were some under each. These observa- 

 tions therefore show that the solutions, though apparently 

 identical to us, appeared to the ants very different, and that, as 



* They are now dead, the last on the 25tli of February. The two queens of 

 F fusca are (March 1883) still alive. 



