Giant bark aphid

This is the largest aphid in North America with adults averaging about 1/4 inch long. They also have long legs which makes them appear even larger. Males and some females are winged but egg laying females are wingless. They are brown with black markings (giving them somewhat of a mottled appearance) and have short, black cornicles. When alive they are often partially covered with a bluish white, waxy secretion. (information from BugGuide)