Pests eaten:
aphids, scales, psyllids, mites

Some favorite plants:
fennel, dill, coriander, Queen Anne's lace, buckwheat, fernleaf yarrow, golden chamomile, tansy, cornflower, and hops.

Ladybugs are red to orange typically with black spots on their backs. Most people are familiar with the small dome-shaped bugs. Adults are approximately 1/3 inch long and typically chew their prey. The larva are very different looking and normally suck on their prey. Ladybugs spend the winter in clusters under rocks, bark or piles of litter. They can also occasionally be found in attics and buildings. Be sure to watch the YouTube video to see the larva stage. I've known of people who thought they were infested by a strange insect when, in fact, they had a lot of baby ladybugs eating their real pests.

YouTube videos:
Ladybugs attacking aphids
Transformation from larval to pupal (ladybug) This last one happens quickly, but you can see what the ladybug larva look like.

UC IPM Online
Cornell University's Biological Control: A Guide to Natural Enemies in North America