40 QUEENS SELDOM PRODUCED IN CAPTIVITY. 
come to maturity in my nests, with one exception not 
a single queen has been produced. 
This was in a nest of Formica fusca, in which five 
queens came to maturity. The nest (which, I need 
hardly say, possessed a queen) had been under observa~ 
tion since April 1879, and the eggs therefore must 
have been laid in captivity. The nest had been richly 
supplied with animal food, which may possibly account 
for the fact. 
It is known that bees, by difference of food, &c., 
possess the power of obtaining at will from the same 
eggs either queens or ordinary workers. Mr. Dewitz,! 
however, is of opinion that among ants, on the con- 
trary, the queens and workers are produced from 
different kinds of eggs. He remarks that it is very 
difficult to understand how the instinct, if it is to be 
called instinct, which would enable the working ants 
to make this difference can have arisen. This is no 
doubt true; but it seems to me quite as difficult to 
understand how the queens, which must have originally 
laid only queen eggs and male eggs, can have come to 
produce another class. Moreover, however great the 
difficulty may be to understand how the ants can have 
learnt to produce queens and workers from one kind of 
egg, the same difficulty exists almost to the same 
extent in bees, which, as Mr. Dewitz admits, do possess 
the power. Moreover, it seems to me very unlikely 
that the result is produced in one way in the case of 
1 Zeit. fir wiss. Zool. 1878, p. 101. 
