Your attic is sheltered from the elements, warm and inviting to several types of bees and wasps. Paper wasps are probably the type of wasp that has inhabited it, although not always. Controlling the various types of wasps and bees can involve chemical or mechanical methods; professionals should deal with large colonies or aggressive species.
Paper wasps are sometimes called umbrella wasps because their nests resemble the shape of an umbrella with exposed honeycomb cells on the bottom. The queen searches out and begins the nest in early summer; early June is the best time to deal with a nest because it's still small.
To control these wasps in your attic, use a small broom if there is only the queen. Use a wasp and hornet spray during the summer. Spray this at the wasps from a distance; the poison makes the wasps "freeze" on contact. If you discover the nest near fall, it may be best to wait until it's cold. The wasps die off in the fall and winter. You can also slip a plastic bag over the nest at night and place it in the freezer or in the sun.
European paper wasps are much more aggressive than their domestic cousins, and their colonies grow into the thousands. Hire a professional if you have an extremely large nest.
Honeybees don't typically nest in the attic, but rather in wall voids. They may use the attic as an entry point to get to the wall voids, so you may encounter them flying around your attic. Honeybees don't cause any structural damage to your home, and you can typically live peacefully with the bees. Exterminating the bees requires some diligence, and you may require the help of a professional pest-control agency. When you exterminate honeybees, remove the leftover honey and bee nest, as rodents and other insects will see this as an all-you-can-eat buffet.
Mud daubers are solitary wasps and very reluctant to sting. Unlike honeybees, paper wasps and hornets, such as yellow jackets, these wasps don't even inhabit the mud nests they build. The female mud dauber will see your attic as an ideal location to construct her many mud tubes because it is warm and protected from the elements. The nests are single tubes of mud on vertical surfaces. Mud daubers are highly beneficial; they paralyse a spider and stuff one spider into each nest for the single larva to feed on. Because of this, they are ideal to have around if you don't like spiders near or in your home. To get rid of mud dauber nests, scrape them off and throw them away.
Like honeybees, yellow jackets may enter through your attic to make their nests in your walls. They may, however, find a suitable spot in your attic. Yellow jackets typically build nests in the ground, sometimes in fallen logs or landscape timbers on the ground. Out of most wasps and hornets, these can be the most dangerous because they are more aggressive. If the nest is exposed, spray with a wasp and hornet spray at night. Because yellow jackets are so aggressive, you may want to hire a professional to take care of the problem.