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 lJarve or pupe would 
be sufficiently intelligent to appreciate, still less to 
remember it, the pupz which were intrusted to ants 
from another nest would bave 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 antenne, 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 pupe 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 
