Adults are about 3/4 inch in length and brownish-red in color. They have long antennae and 3 pairs of legs. They make a loud buzzing noise that sounds similar to a bumblebee when they are in flight.
The western conifer seed bug does not bite or sting, but it can become a pest in structures. These rather large insects can invade homes, offices and buildings in large numbers looking for shelter from the cold. Outdoors, they may over winter in such places as bird nests, under bark or in leaf litter.
The western conifer seed bug feeds on cones and seeds from a large variety of trees such as pine, spruce, hemlock and holly.
In spring, the female will lay her eggs in the needles of a host tree. The eggs will hatch in 10 to 14 days, the emerging nymphs look similar to the adult, but are wingless and orange-brown, changing to a reddish-brown as they mature. By the end of summer they should reach adulthood.