Giant Mesquite Bug

Thasus neocalifornicus · Order: Hemiptera · Family: Coreidae

No source yet on danger. We have no source yet on whether it bites, stings or damages anything.
Giant Mesquite Bug
Photo: Logan J.L. Bradley, CC BY

Adults are about two inches long and are dark brown with striped legs and antennae. They live in the Sonoran Desert from southwestern Arizona to Baja California Sur, often gathering on mesquite trees.

Source: Wikipedia

Size

Adults measure roughly two inches in length.

Source: Wikipedia

Where it lives

They inhabit the Sonoran Desert, ranging from southwestern Arizona into Baja California Sur.

Source: Wikipedia

When you see it

Populations are most common around Tucson, Arizona and the southern tip of Baja California Sur.

Source: Wikipedia

Where it comes from

Their native range is the Sonoran Desert of the southwestern United States and northwestern Mexico.

Source: Wikipedia

Lookalikes

It was previously confused with T. gigas or T. acutangulus until distinguished in 1995.

Source: Wikipedia

Where it is found in the US

Recorded in 3 of 51 states and DC. Most records: Arizona, Texas, New Mexico.

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

Source: GBIF

Months it is reported in the US

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Source: GBIF

More photos

Giant Mesquite Bug photo 3
Photo: Daniel McNair, CC BY
Giant Mesquite Bug photo 4
Photo: Rachel Lee Harper, CC BY
Giant Mesquite Bug photo 5
Photo: Ken-ichi Ueda, CC BY
Giant Mesquite Bug photo 6
Photo: Jonathan Eisen, CC BY

Questions people ask

How can I tell a giant mesquite bug apart from similar species?

Look for the bright white-red warning colors on nymphs and the dark brown body with crimson-black striped legs on adults; other species lack this exact pattern.

Source: Wikipedia

Where are giant mesquite bugs found?

They live in the Sonoran Desert, from southwestern Arizona down into Baja California Sur.

Source: Wikipedia

Same family (Coreidae)

Western Conifer Seed BugWestern Conifer Seed BugLeptoglossus occidentalisDamages trees, gardens or cropsSquash BugSquash BugAnasa tristisDamages trees, gardens or cropsDock BugDock BugCoreus marginatusAcanthocephala terminalisAcanthocephala terminalisAcanthocephala terminalisHarmlessEastern Leaf-footed BugEastern Leaf-footed BugLeptoglossus phyllopusDamages trees, gardens or cropsGiant leaf-footed bugGiant leaf-footed bugAcanthocephala declivis

Sources

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

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

Text written 2026-10-24 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-24.

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.