Photograph the insect from above, in focus, with something for scale beside it. Size and the shape of the waist and antennae do most of the work, and they are the details memory loses first.
Lookalikes
Two or three insects that pass for each other, and the feature that separates them.
- Asian lady beetle vs ladybugBoth are lady beetles.
- Water bug vs cockroachWater bug is a nickname, not a species.
- Termite vs flying antThree features separate them.
- Wasp vs hornet vs yellow jacketSize, color and the nest separate them.
- Fungus gnat vs fruit flyWhere it came from answers it faster than how it looks.
- Bugs that look like bed bugsSize sorts most of it.
In the house
The ones that turn up in bathrooms, basements, pantries and wardrobes.
- Carpet beetleCarpet beetles are small oval beetles, 1/16 to 1/8 inch long, that Kentucky extension describes as black or mottled with white, brown, yellow and orange.
- Drain flyA drain fly is a tiny, fuzzy, moth-like gnat that sits still on the wall near a sink or a floor drain and makes short hopping flights when disturbed.
- Camel cricketA camel cricket is the humpbacked, wingless, long-legged cricket that jumps out of a basement corner.
- House centipedeThe fast, many-legged thing in a bathroom is almost always a house centipede.
- SilverfishA silverfish is a wingless, flat, teardrop-shaped insect covered in silvery scales, with long thread-like antennae and three tail-like appendages at the rear.
- Weevils and flour beetlesThe snout tells you which group you have.
In the garden
The ones you meet outdoors, and on the sunny side of the house in autumn.
- Boxelder bugA boxelder bug is a black true bug with thin red lines, about half an inch long, that gathers in numbers on the sunny side of a wall in autumn.
- Stink bugThe brown marmorated stink bug is a shield-shaped brown bug about 17 mm, or two thirds of an inch, long and almost as wide as it is long.
- EarwigAn earwig is the flat, dark reddish brown insect with a pair of claw-like pincers at the rear.