Bug FAQNarrow Searcher Beetle
Calosoma externum · Order: Coleoptera · Family: Carabidae
Also called: Narrow Searcher
In the United States they are widespread and the adults prey on caterpillars of several grass-hopper and moth species.
Source: Wikipedia
How to recognize it
The beetle’s body is black with bluish reflections along the margins.
Source: Wikipedia
Size
Adults measure between 28 and 35 mm in length.
Source: Wikipedia
Where it lives
It inhabits fallow fields and the edges of standing water.
Source: Wikipedia
Life cycle
The species was first described by Say in 1823.
Source: Wikipedia
Where it comes from
This beetle is found throughout most of the United States.
Source: Wikipedia
Where it is found in the US
Recorded in 27 of 51 states and DC. Most records: Kansas, Kentucky, Oklahoma, Missouri, Iowa, Ohio, Tennessee, Illinois.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: introduced in Canada; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What do Narrow Searcher Beetles eat?
Adults feed on caterpillars of several grass-hopper and moth species, including Melanoplus and Malacosoma.
Source: Wikipedia
Same family (Carabidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Calosoma_externum
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-26 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-26.