Household Bug Reference
Every species in the Benign vs Nuisance Bug Classifier’s catalog, in one table — what to look for, its classification, its typical size band, when it tends to show up, and the one exclusion step that actually applies to it.
The full catalog, grouped by classification
Beneficial — worth leaving alone
| Bug | What to look for | Typical size | Seasonal signal | Exclusion focus |
|---|---|---|---|---|
| Ladybug (Ladybird Beetle) | Small, domed, often orange-red with black spots; six short legs on an oval body. | Not sized | Not tracked seasonally | No exclusion needed |
| Praying Mantis | Long body, a triangular head that swivels, and large front legs held folded upward. | Not sized | Not tracked seasonally | No exclusion needed |
| Common House Spider | Rounded tan-to-brown abdomen; builds a messy, irregular (not orb-shaped) web in corners. | Medium (10–20mm) | Winter, Summer, Fall | No exclusion needed |
| Ground Beetle | Shiny black or dark bronze, long running legs, usually only seen at night on the ground. | Not sized | Not tracked seasonally | No exclusion needed |
| House Centipede | Long, flattened body with up to 15 pairs of very long legs; moves in short, fast bursts. | Large (20–40mm) | Not tracked seasonally | No exclusion needed |
Harmless Nuisance — unwelcome, not damaging
| Bug | What to look for | Typical size | Seasonal signal | Exclusion focus |
|---|---|---|---|---|
| Boxelder Bug | Black with red-orange wing-edge markings; gathers by the dozens on sun-warmed exterior walls. | Not sized | Winter, Fall | Seal foundation cracks and utility penetrations with silicone caulk or expanding foam. |
| Cluster Fly | Dull gray, housefly-shaped, sluggish and slow-moving, with fine golden hairs on the thorax. | Not sized | Winter, Fall | Seal foundation cracks and utility penetrations with silicone caulk or expanding foam. |
| Brown Marmorated Stink Bug | Mottled brown, shield-shaped body, with alternating light-and-dark banded antennae. | Not sized | Winter, Fall | Seal foundation cracks and utility penetrations with silicone caulk or expanding foam. |
| Earwig | Reddish-brown, elongated body with a pair of pincer-like cerci at the tail end. | Medium (10–20mm) | Not tracked seasonally | Fix leaks and run a dehumidifier — moisture draws in far more household pests than food does. |
| Pillbug (Roly-Poly) | Segmented gray armor-like shell; rolls into a tight ball when disturbed. A crustacean, not an insect. | Not sized | Not tracked seasonally | Fix leaks and run a dehumidifier — moisture draws in far more household pests than food does. |
| German Cockroach | Light tan to brown, roughly half an inch long, with two dark parallel stripes behind the head. | Medium (10–20mm) | Not tracked seasonally | Fix leaks and run a dehumidifier — moisture draws in far more household pests than food does. |
Property-Damaging — worth acting on
| Bug | What to look for | Typical size | Seasonal signal | Exclusion focus |
|---|---|---|---|---|
| Silverfish | Silvery, teardrop-shaped, flattened body with three long tail bristles; wingless and fast. | Not sized | Not tracked seasonally | Fix leaks and run a dehumidifier — moisture draws in far more household pests than food does. |
| Clothes Moth | Small, pale gold or buff-colored moth that avoids light and is rarely seen flying in the open. | Not sized | Not tracked seasonally | Swap cardboard for sealed plastic bins — cardboard is both food and shelter for several pests. |
| Carpet Beetle | Small, round, mottled black/white/orange scales as an adult; larvae are bristly and carrot-shaped. | Small (3–10mm) | Not tracked seasonally | Swap cardboard for sealed plastic bins — cardboard is both food and shelter for several pests. |
| Termite | Pale, soft-bodied, straight antennae, and a broad waist with no pinch — see our Ants vs Termites guide. | Not sized | Spring | Maintain a 6+ inch gap between soil and any wood structural member. |
| Powderpost Beetle | Small reddish-brown beetle; the reliable sign is fine powdery frass and pinhole exit holes in bare wood. | Not sized | Not tracked seasonally | Repair or replace decayed wood and keep exterior wood painted or sealed. |
Classification, size band, season, and exclusion note are all read directly from the same classifyBug(), SIZE_BANDS, getSeasonalPests(), and RISK_FACTORS data the tools above use — this table has no separate, hand-typed copy of any of those facts.
How this table is built
Every row starts from the same 16-species catalog behind the Benign vs Nuisance Classifier, so the name, classification, and one-line note in each row are never re-typed — they’re the live output of that tool’s own lookup function. Two more tools contribute the remaining columns wherever they genuinely apply. A size band shows up only when this species’ name matches one of the worked examples already listed inside the Bug Size Estimator’s own size bands (five of the sixteen species do); a season shows up only when the species has an actual entry in the Seasonal Pest Calendar’s dataset (five species do, all overwintering or wood-swarming pests with a genuine seasonal signal).
The exclusion column works the same way in reverse: for the property-damaging and harmless-nuisance species, it surfaces the single most relevant recommendation from the Infestation Risk Checklist’s own weighted factor list — a termite row points at the wood-contact and moisture factors because that’s what its own catalog note cites, not because we invented new prevention advice for this page. Beneficial species carry no exclusion note at all, because excluding them isn’t the point.
Frequently Asked Questions
Where does the classification in this table come from?
The same classifyBug() lookup behind the Benign vs Nuisance Classifier tool. This page doesn't re-decide or re-type any category — it renders whatever that function currently returns for every species in its catalog, so the two always agree.
Why do only some rows have a size band or a season?
A size band only appears when a species' name matches one of the worked examples already listed in the Bug Size Estimator's own size bands, and a season only appears when that species has an entry in the Seasonal Pest Calendar's dataset. Rather than guess a band or a season for the rest, we leave those cells blank — an honest "not tracked" beats an invented number.
Is this a complete list of household bugs?
No — it's the same 16-species catalog the classifier tool ships with, which covers the household bugs people ask about most often. It isn't a full regional field guide, and it deliberately excludes anything that requires a medical or bite/sting call, which isn't what an identification reference should be making.
Why isn't there an exclusion note for the beneficial species?
Exclusion means keeping something out, and the beneficial species on this list — ladybugs, house spiders, ground beetles, praying mantises, house centipedes — are the ones you generally want to leave in place. We didn't force a recommendation onto a row where the honest answer is "no action needed."
Identification and prevention reference only — not pest-control, pesticide-application, or medical advice. See our Disclaimer for details.
Use it with
- Benign vs Nuisance Bug Classifier— look up one specific bug interactively instead of scanning the full table.
- Bug Size Estimator— enter a measured length to get its size band directly, for a bug not already sized in the table above.
- Infestation Risk Checklist— turn the exclusion column above into a scored, prioritized checklist for your own home.
- Seasonal Pest Calendar— see the full month-by-month picture behind the seasonal signal column, for any month and hemisphere.