Smiling Mason Wasp

Ancistrocerus campestris · Order: Hymenoptera · Family: Vespidae

No source yet on danger. We have no source yet on whether it bites, stings or damages anything.
Smiling Mason Wasp
Photo: Louise Woodrich, CC BY

Adult Ancistrocerus campestris are about a centimeter long. They can be recognized by a smile-like pattern on the back of their thorax. These wasps hunt caterpillars of the Amphisbatidae and Gelechiidae families.

Source: Wikipedia

How to recognize it

A distinctive smiley-face marking appears on the rear of the thorax.

Source: Wikipedia

Size

Adults grow up to about 10 mm in length.

Source: Wikipedia

What it eats

It preys on caterpillars belonging to the Amphisbatidae and Gelechiidae families.

Source: Wikipedia

Where it is found in the US

Recorded in 36 of 51 states and DC. Most records: Virginia, Maryland, New York, Illinois, Ohio, North Carolina, Georgia, Pennsylvania.

Darker = more records. Counts are museum and citizen-science records, not population size.

Source: GBIF

Status: native in North America; native in Canada. Source: iNaturalist

Months it is reported in the US

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Source: GBIF

More photos

Smiling Mason Wasp photo 3
Photo: Tom Romeo, CC BY
Smiling Mason Wasp photo 4
Photo: John Abrams, CC BY
Smiling Mason Wasp photo 5
Photo: Matt Pelikan, CC BY
Smiling Mason Wasp photo 6
Photo: jonsense, CC BY

Same family (Vespidae)

European HornetEuropean HornetVespa crabroCan stingBald-faced HornetBald-faced HornetDolichovespula maculataCan stingGerman YellowjacketGerman YellowjacketVespula germanicaCan stingEastern YellowjacketEastern YellowjacketVespula maculifronsCan stingYellow-legged HornetYellow-legged HornetVespa velutinaCan stingWestern YellowjacketWestern YellowjacketVespula pensylvanicaCan sting

Sources

  • Wikipedia: https://en.wikipedia.org/wiki/Ancistrocerus_campestris

Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia

Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.

How this page works

This is one bug's fact sheet. The colored box at the top says whether it is dangerous. Sections below cover how to recognize it, whether it is a pest, and how to deal with it. The US map shows which states have records; tap a state to see other bugs there.

Every fact on Bug FAQ comes from a named source (university extension sites, government agencies, GBIF, iNaturalist, Wikipedia). The source is linked next to each section. If we have no source for something, we leave it out.