TO THE NEST AFTER COMING TO MATURITY. 135 



glasses, with ants from another nest of the same species. 

 Now, as already mentioned, if the recognition were 

 effected by means of some signal or password, then, as 

 we can hardly suppose that the larvae or pupae would 

 be sufficiently intelligent to appreciate, still less to 

 remember it, the pupae which were intrusted to ants 

 from another nest would have the password, if any, of 

 that nest, and not of the one from which they had been 

 taken. Hence, if the recognition were effected by 

 some password or sign with the antennae, they would 

 be amicably received in the nest from which their 

 nurses had been taken, but not in their own. 



I will indicate the nests by the numbers in my 

 note-book. 



On August 26 last year I put some pupae of 

 Formica fusca from one of my nests (No. 36) with two 

 workers from another nest of the same species. Two 

 emerged from the chrysalis state on the 30th ; and on 

 September 2 I put them, marked as usual, into their 

 old nest (No. 36) at 9.30 a.m. At 9.45 they seemed 

 quite at home, and had already been nearly cleaned. 

 At 10.15 the same was the case, and they were scarcely 

 distinguishable. After that I could no longer make 

 them out ; but we watched the nest closely, and I 

 think I can undertake to say that if they had been 

 attacked we must have seen it. 



Another one of the same batch emerged on August 

 18, but was rather crippled in doing so. On the 21st 

 I put her into the nest (No. 36), This ant was at once 



