Numbers
Over 1700 Northamerican species in 21 subfamilies.
Size
Small, rarely over 15 mm long.
Identification
Antennae apparently with 16 or more segments.
Hind trochanters 2-segmented.
One or no recurrent veins.
Usually black or brown; some common species with reddish markings.
Females often with long ovipositors.
Additional information:
Species in the family Braconidae are separated from those in Ichneumonidae by having none or just one recurrent vein rather than two.
Life Cycle
A large group with many life histories adapted to parasitizing hosts as diverse as aphids, bark beetles, and foliage-feeding caterpillars. Many species are egg-larval parasitoids, laying eggs within host eggs and then not developing until the host is in the larval stage. Unlike Ichneumons many pupate in silken cocoons outside the body of the host and others spin cocoons entirely apart from the host.
Remarks
Some are very useful as pest controls.
