The Assassin bug:
A viscous-looking bug that measures from ¼ inch to 1-inch long, with a cone-shaped head and curving beak. Their bite can be painful to humans and some species squeak when captured. Females lay single eggs in cracks, under rocks or in other sheltered spots in the summer and the new adults emerge the following June. Assassin bugs prey on many garden pests including flies, mosquitoes, beetles and large caterpillars. Adult and nymph Assassin bugs stab their prey with a long, pointed "beak" that is held, folded under their bodies when not feeding.
The Damsel bug:
Among the more predacious insects, Heteroptera feeds on insect eggs, Aphids, and small caterpillars. Damsel bugs are divided into two types. One measures about 8mm long and is colored a yellow-brown displaying well-developed wings while the other is larger, and shiny black. This one has much shorter wings. Also included in this beetle category is the well known "Dragon-fly", which prays primarily on Aphids.
Many of us have seen this little one; with its light green body, golden/copper-colored eyes and large transparent wings that sport delicate "veins" similar to leaves. Adult Lacewings measure about ½ to ¾ inch long. The larvae are small, grayish-brown and narrow and they have pincher-like mandibles. Eggs are found on plant stems and foliage; they are laid singularly or in small groups. These delicate looking bugs prey on a variety of other insects like Aphids and other small insects, insect eggs, Spider mites, Leafhopper nymphs, Whiteflies and small caterpillars. You can even support good Lacewing egg health in your garden. Check out the links I've provided for more information.
Sometimes mistaken for the larger Damsel bug, this beetle preys primarily on soil-dwelling insects like Grubs, Cutworms and Maggots, all of which attack your lawn and can be a chore to get rid of. These beetles vary in shape and size, but most of them are shiny and darkly colored and range from 1/8 to 1-inch long. They are not known to bite humans despite their ferocious-looking features. They feed mostly at night and hide during the day, and some species even snack on slugs and snails.
I don't know a single person who is unfamiliar with the Ladybug. And though most of us prize these gentle insects with protecting our roses from Aphids, it is their larvae, which are most valuable-a soft-bodied, alligator-shaped bug with black and orange markings. Both the larvae and the adult Lady beetle feed on other soft-bodied insects like Aphids, Mealy bugs, scale insects, Spider mites and insect eggs. A note about purchasing and releasing these beetles into your garden; they don't often hang around for long without the right plants. Check out the link I pasted at the bottom of this article for tips on attracting them.
Solider Beetle (Leather wings):
Even most children know this character. Distinctive with its red body and black wings, this beetle is easy to ignore in the garden as it is not known for biting humans or pets, and it can really keep the peace. It is typically about ½ inch in length and feeds on Aphids, caterpillars, Grasshopper eggs, and the larvae of other beetles. It has also been known to eat other various insects in the garden when they are available.
California Praying Mantis:
The California mantis lives along the Pacific coast into Northern California and Oregon. The species can be many different colors in order to blend into its different environments, including brown, yellow and green. The California mantis is smaller than some species, usually up to 2 1/2 inches long. Like other mantis species, the California mantis consists on a diet of other, usually harmful, insects.
Don't forget about the benefits of having plenty of earthworms. They cultivate almost continually-breaking down organic matter into useable nutrition for our plants. They are great for composting and cleaning up around the base of trees.