Sawflies are represented by several families of stingless wasps.  They are thought to be the most primitive of the wasps because of their complex wing venation and because their larvae are vegetarians.  Females use a sawlike organ to deposit their eggs in leaves or twigs, hence the name Sawfly.  There are about 730 species of Common Sawflies (Tenthredinidae) in North America. The larvae resemble caterpillars of butterflies or moths.  Adults appear to mimic stinging wasps.  Webspinning Sawflies (Pamphiliidae) live as larvae in webs or rolled up leaves.  Argid Sawflies (Argidae) are recognized by the long terminal segment of the antennae.  Most larvae feed on leaves of the host plant. 

Horntails (Siricidae) are large, cylindrical wasps that look threatening but are actually harmless.  The female drills into dead or dying trees to deposit her eggs and also injects a wood-rotting fungus to make it easier for the larva to chew tunnels in the tree.  The larvae are wood borers and are preyed upon by Ichneumon wasps.  There are about 19 species of Horntails in North America.