274 NATURAL HISTORY. 
467. The family of Sawflies is quite an extensive aber- 
rant family. They are so called from a curious double 
saw in the ovipositor, with which they make holes in the 
branches and other parts of trees for the deposit of their 
egos. Carpenter mentions one species in England, whose 
larvee are very destructive to turnips, devastating a whole 
field in a few days by devouring the soft tissue of the 
leaves; and he states that the most effectual remedy has 
been found to be the introduction of ducks into the fields, 
as they very greedily devour the larve. 
468. Of the Aculeate division of the Hymenoptera we 
make two subdivisions—the Predaceous, or those which 
live on prey, and the Melliferous, or honey-collecting 
stingers. 
469. There is one group of the Predaceous division, 
including several families, which may be called, from their 
peculiar habits, diggers. They are known commonly as 
Sand and Wood Wasps. They are solitary—that is, do 
not live in communities. They therefore are all males 
and females, and have no neuters or workers. The fe- 
males commonly dig out cells in the ground, or in posts 
and timbers. In these they deposit with their eggs in- 
sects which they have killed, so that the larvae, when 
hatched, may have something to live upon. Sometimes 
the insects thus deposited are only stung sufficiently to 
render them powerless. Decomposition is thus prevent- 
ed, and the larvee, when they come forth from the eggs, 
kill the insects and devour them. The perfect insects 
are active in their habits, flying about and running over 
sand-banks with their wings in constant motion. They 
are fond of the nectar of flowers,a very different food 
from that which they devour in the greedy larva state. 
Those which are sand-burrowers have strong brushes on 
their legs with which they excavate their nests, while 
the wood-burrowers have powerful mandibles with tooth- 
like projections, which convert the wood into sawdust 
in making the burrow. 
