Field plate · Dolichovespula maculata
Bald-faced hornet
Black-and-ivory, football-nest builder in trees and on gable ends. Not a true hornet — a large aerial yellowjacket with a short temper at home.
Plate 14 of 28. Drawn in profile to the identification marks named below; the scale rule is a drawing convention — sizes are given in the text.
Identification marks
Workers 12–15 mm, queens larger; black with ivory-white markings on the face, thorax, and abdomen tip. The nest is the giveaway: a grey, papery, enclosed football hanging from a branch or eave, growing all summer.
Look-alikes it is confused with
European hornet (much larger, brown and yellow, attracted to lights at night, nests in hollows — established and widespread in Pennsylvania) and large yellowjackets without the ivory face.
Where it hides in a house
Tree limbs, large shrubs, and the peaks of gables and sheds, usually several meters up. Traffic at a nest entrance is constant on warm days.
Health & property risk, stated plainly
Vigorous nest defence over a wide radius, and a sting that the colony will repeat. Nests low over paths, bus stops, and play equipment are genuine hazards by August.
What actually works
Distance is the treatment for most nests: they are annual, die at frost, and old nests are not reused. Removal mid-season means a pro treating the nest in the cool of night and physically removing it once activity ends.
What doesn't
Shooting, burning, or knocking down an occupied nest — every account of this ends the same way — and daytime attempts at height.
When to call a licensed pro
Yes, for any occupied nest that must come down before frost. This is ladder, suit, and timing work.