Hornets: The most common one is the bald face hornet (Vespula maculata). They have black and white patterns on their face, thorax and abdomen, and are around ¾ of inch long. Adults drink nectar, fruit juices, and occasionally eat other insects. Larvae feed on insects provided pre-chewed by adults. In the spring a single female chews wood to build a small, pendant nest out of gray pulp. The first generation includes only female workers, which bring food to the growing larva population and expand the nest. The nest is usually constructed in the open and consists of many layers of cells that are covered to form an egg shaped shelter that can be over 2 feet long. The doorway is located at the bottom which is fiercely guarded, so beware. They can sting repeatedly. I’ve noticed that when a hornet gets after me, it tends to go for the head and face. I’ve had them slam into my hat or forehead but not sting, sort of like a warning shot and I quickly get the message. In late summer males mature from unfertilized eggs and mate. They die along with old queens, workers, and any immature young. Only young, mated females overwinter in soil or leaf litter.
There is foreign hornet in our area that was accidentally introduced to the U.S. in the late 1800s, called the European hornet. It’s quite large with a 1-1½ inches long body that is reddish brown on the front, and a yellow abdomen with dark cross-bands. Its lifestyle is similar to other hornets, but they are carnivores, preying on other insects. While not known to be aggressive, I have been stung by one and it was very painful.
Dirt Daubers: Also known as mud daubers or organ pipe mud daubers (Sceliphron caementarium). These insects remind you of waspers, but have a thread-like waist that is longer. Daubers are around 1-1 1/8 inches long, and usually appear black or bluish with a metallic sheen. They twitch their wings constantly. Adults drink nectar, while larvae feed on spiders provided by the adult. Dirt daubers are the loners of the Vespid family, forming no social colony. Using her mandibles (jaws), single female shapes moist mud into small balls and transports them to a vertical surface, where she builds tubular cells. Into each cell the mother dauber stuffs 1 paralyzed spider immobilized by venom, lays 1 egg on the spider, then closes the cell with mud. Additional cells are built parallel to the first. Each larva feeds on its spider until adulthood, and then digs out to start life.
A good book on insect identification is the National Audubon Society Field Guide to North American Insects and Spiders.