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 v/ith the bee-hives ; for, said she, " since 

 they were placed in the hot-house all the trees have pro- 

 duced fruit in abundance." AYe 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- 



