234 NORTH AMERICAN INSECTS. 
upon the prospect of a large crop of fruit, when she inform- 
ed us that her gardener had never succeeded in raising 
more than one dishful of fruit from all those trees. We 
assured her that if she would place in her green-house a 
few full bee-hives there would be a charm about them that 
would insure her an abundant harvest of fruit. Two years 
afterward we visited that lady in Moscow, on our return 
from the Caucasus, when she desired an explanation of the 
charm connected with the bee-hives; for, said she, ‘‘ since 
they were placed in the hot-house all the trees have pro- 
duced fruit in abundance.” We then explained to her that 
the bees collect the pollen of the flowers, and at the same 
time bring this fertilizing farina of the stamens in contact 
with the germ, which then produces the fruit. 
So useful to man are all the insects of this order, that we 
can not find fault, notwithstanding there are no other in- 
sects which, when provoked, take revenge upon us with 
dagger and venom, and notwithstanding a few genera spoil 
the wood of the carpenter. Their good so far overbalances 
their evil deeds, that the latter are hardly worthy of men- 
tion. 
Of the Hymenoptera of North America we shall now 
have time to notice only a few of the most interesting, be- 
cause the most useful genera and species. 
Figure 64, 

The Onerate Gall-wasp. 
The Gall-wasp (Cynips). 
This is a genus which is very common, and is composed 
of a great number of species. Its perfect insects are gen- 
