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I have bred up to thirteen 7richogramma from one Le- 
pidopterous egg. I have experimented by letting a Tricho- 
gramma female lay its eggs on the eggs of Palomena 
prasina L. The female was very willing to lay, but the 
result was that the Palomena eggs shrivelled in and died 
and only one single gave a large deformed 7richogramma, 
which died almost immediately after it emerged. I have 
also made the same experiment with a large number of 
the eggs of Macrothylacia rubi, with some female Tricho- 
gramma. They apparently had no difficulty whatever in 
cutting a hole in these eggs, which could be supposed 
to be of a very strong texture, but the result was negative, 
all the young rubi larvæ hatched and although they were 
kept in confinement a long time showed no sign of having 
been attacked. It may be, however, that the parasite laid 
its eggs too late as the ruwbi larva hatched a couple of 
days later. I am of the opinion, however, that if it could 
be managed to get a species to lay its eggs on another 
host than the usual and healthy specimens resulted, these 
would get their antennal reactions altered as to be able 
to attack this new host. This would have its importance 
in an economical respect. 
When the specimens emerge they are often fully deve- 
loped at once, no time being occupied after emerging 
for developing or drying the wings etc. I have sometimes 
seen as many as eight female 7richogramma on a bunch 
of Sialis eggs in the act of depositing their eggs, which 
confirms the fact that when breeding the specimens do 
not belong to one brood, thus accounting for the reason 
why they pair immediately after emerging, which never 
takes place with individuals of the same parents, a case 
I have often had opportunity to observe. 
With regard to hibernation, nothing is known to me. 
Some species as already mentioned are to be found from 
early summer to far into the autumn in certain localities, 
but of where they then go and where they hide themsel- 
