Bug FAQFour-toothed Mason Wasp
Monobia quadridens · Order: Hymenoptera · Family: Eumenidae
Source: Wikipedia
Females have a wingspan of 14 to 18 mm while males are smaller at 11 to 14.5 mm. It hunts small caterpillars and also collects pollen.
Source: Wikipedia
How to recognize it
The abdomen is all black except for a wide ivory band on the first segment.
Source: Wikipedia
Does it bite or sting?
Both sexes can sting; males can also deliver a painful jab without venom.
Source: Wikipedia
Where it lives
It nests in cavities such as abandoned carpenter-bee tunnels, old mud-dauber nests, and hollow plant stems.
Source: Wikipedia
What it eats
Its diet consists mainly of micro-moth caterpillars from several families and a large amount of pollen.
Source: Wikipedia
When you see it
One generation emerges in summer, the other overwinters as pupae and emerges in spring.
Source: Wikipedia
Lookalikes
It looks very similar to Euodynerus bidens in size and colour.
Source: Wikipedia
Where it is found in the US
Recorded in 39 of 51 states and DC. Most records: Texas, Virginia, New York, Massachusetts, Maryland, Ohio, Florida, 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
Source: GBIF
More photos
Questions people ask
Can the four-toothed mason wasp bite or sting?
Yes, it can sting, and males can give a painful needle-like jab that does not inject venom.
Source: Wikipedia
How big is this wasp?
Females are 14 to 18 mm across, while males are 11 to 14.5 mm.
Source: Wikipedia
What does it eat?
It feeds on small caterpillars of micro-moths and also gathers pollen.
Source: Wikipedia
Where does it live?
It nests in hollow cavities like abandoned bee tunnels, old mud-dauber nests, and plant stems.
Source: Wikipedia
Same family (Eumenidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Monobia_quadridens
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.