Bug Eggs and Larvae: What Laid These Eggs?

Eggs and larvae mean a pest is breeding, not just passing through, and where you found them is the biggest clue. Mattress seams point to bed bugs, food to pantry moths, closets to carpet beetles or clothes moths, drains to drain flies and trash to fly maggots. The one thing to do: photograph them next to a coin and note the exact spot.

This page matches eggs and larvae to the pest that laid them and says how to confirm it. It rests on EPA and UC IPM guidance; a county extension office can identify a sample.

What Laid These Eggs? Start With Where They Are

Main clue	Size and look	Where	From
Tan, purse-shaped capsule with ridges	About 1/4–3/8 in	Cabinet hinges, corners, carried by females	Cockroaches
Pearly white eggs, often in clusters	About 1 mm, pinhead-size	Mattress seams, bed frame cracks	Bed bugs
Tiny white ovals like grains of salt	About 0.5 mm	Pet beds, carpets where pets sleep	Fleas
Fuzzy, banded, carrot-shaped larvae and hollow bristly skins	Up to 1/4 in	Closets, under furniture, carpet edges	Carpet beetles
Off-white caterpillars with silk webbing	Up to 1/2 in	Flour, cereal, nuts, birdseed, pet food	Pantry moths
Creamy larvae inside silk tubes on fabric	Up to 1/2 in	Wool clothes, rugs	Clothes moths
Small, gray, worm-like larvae in slime	Under 1/2 in	Inside drains and overflows	Drain flies
Cream-white, legless maggots	Up to 1/2 in	Trash cans, spoiled food, pet waste	House flies
Wriggling larvae hanging at the surface	About 1/4 in	Standing water outdoors	Mosquitoes
Barrel-shaped, pale green eggs in a neat cluster	Clusters of about 20–30	Undersides of leaves	Stink bugs
Round or teardrop silk ball, white to brown	About 1/4–1/2 in	Webs in corners, garages and basements	Spiders

A dark brown, purse-shaped cockroach egg case with a ridged seam, stuck to a wall

A cockroach egg case glued to a wall: hard, dark brown and ridged along one edge. Photo: KKPCW (CC BY-SA 4.0), via Wikimedia Commons.

Cockroach Egg Cases: A Hard, Ridged Capsule

Cockroaches lay eggs inside a hard capsule called an ootheca. German cockroach females carry it sticking out of the tail end until the eggs are almost ready to hatch; larger cockroaches drop or glue theirs in hidden spots. See cockroach eggs and how to tell a baby cockroach from other small bugs.

Main clue: a tan, ridged, purse-shaped capsule 1/4 to 3/8 inch long near cabinet hinges and corners.

Bed Bug Eggs: Pearly White, Pinhead-Sized

The EPA describes bed bug eggs as tiny, about the size of a pinhead, and pearly white. They’re glued into seams and cracks near where people sleep, along with pale shed skins from the young bugs.

Main clue: pinhead-size pearly white eggs glued into mattress seams or bed frame cracks.

Carpet Beetle Larvae: Hairy, Striped, Shedding Skins

Small, hairy, striped larvae in a closet or under a bed are carpet beetle larvae, sometimes called woolly bears. They shed their skins many times, so hollow bristly skins are often the first thing people find; the signs of carpet beetles guide shows them.

Main clue: fuzzy, banded larvae up to 1/4 inch and hollow bristly skins in closets or along carpet edges.

Flea Eggs and Larvae: Hidden Deep in the Carpet

Flea eggs fall off pets into bedding and carpet. Larvae are thin and white, avoid light and feed on flea droppings, so they hide deep in carpet fibers and under furniture (UC IPM).

Main clue: tiny white ovals like grains of salt where pets sleep.

Food, Drain and Trash Larvae: Webbing, Slime or Maggots

Off-white caterpillars with silk webbing in flour, cereal, nuts, birdseed or pet food are pantry moth larvae. Small gray, worm-like larvae in the slime inside drains and overflows are drain flies. Cream-white, legless maggots in trash cans, spoiled food or pet waste are house fly larvae.

Main clue: silk webbing in food means pantry moths; larvae in drain slime mean drain flies; legless maggots in trash mean house flies.

How to Confirm What Laid Them

Look with a flashlight and a magnifier, and take a close-up photo next to a coin for scale.
Note exactly where they were: seam, shelf, drain, carpet or leaf.
Bag a few in a sealed bag or jar and have them identified by a county extension office.

What to Do Next: Treat the Breeding Spot

Eggs mean the source is close by. Open the pest’s page in the table for what to do; for food pests, how to get rid of pantry moths starts with throwing out the infested package.