# Bat bug

*Cimex adjunctus*

**Identification confidence:** Needs an expert — Bat bugs and bed bugs are separated by the length of hairs on the pronotum, which needs a microscope. This is exactly the case where a specimen should go to an extension entomology lab — and the distinction changes everything, because the real problem is a bat roost.


## How to recognise it

- Essentially identical to a bed bug in size, colour, and flattened oval shape at normal viewing distance.
- The fringe hairs along the edge of the pronotum are longer than the width of an eye, against shorter than an eye width in the bed bug. This requires magnification and is the only reliable separator.
- Found in association with attics, chimneys, wall voids, and light fixtures rather than concentrated around beds.

## What it leaves behind

- Insects appearing at ceiling level, around light fixtures, or dropping from above.
- Signs of a bat roost — guano accumulations, staining at gaps in the roofline, or noises at dusk.

## Why an infestation persists

Bat bugs feed primarily on bats and move into living space when the bat colony leaves or is excluded. Treating them as bed bugs misses the point entirely: the source is the roost. Bat exclusion is also regulated in many states because several bat species are protected and exclusion is prohibited during maternity season, which is a genuine legal constraint, not a formality.


## Where it occurs

Across the United States wherever bats roost in structures, most commonly reported in the Midwest and East.

## What prevents it

- Have the roost identified and addressed first; the insects follow the bats.
- Do not attempt bat exclusion without checking your state's protected-species rules and maternity-season restrictions.

## Commonly confused with

- **Bed bug** (*Cimex lectularius*) — Adults are 4 to 5 mm, roughly the size and shape of an apple seed — flat and oval when unfed, swollen and elongated to nearly cylindrical after feeding.

**Verdict:** professional-required. The underlying problem is a bat roost, and bat exclusion is legally restricted in most states during maternity season. Several bat species are protected under state and federal law.


Source: https://againstpest.shop/identify/bed-bugs/bat-bug/