Ants
Large black or red-and-black ants that hollow out damp wood to nest. They do not eat it, so what you find is sawdust rather than missing wood.
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Ants
A stinging ant whose mound has no opening. They come and go through tunnels that surface somewhere else.
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Ants
Crush one and smell it. That is the whole identification, though the smell is not really coconut.
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Bed Bugs
Bed bugs feed on blood, hide within a few feet of where you sleep, and fit into a crack no wider than a toothpick. They do not spread disease, and they have nothing to do with how clean your home is.
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Cockroaches
Two big dark roaches that share a habit. Both live outdoors and come inside, unlike the German cockroach.
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Cockroaches
One egg case releases up to 40 nymphs, and a single mated female can put thousands of offspring into a building in under a year. This is the one cockroach that does not live outdoors at all, so if it is inside, it is breeding inside.
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Fleas
The fleas on the pet are the small end of it. Most of an infestation is eggs and larvae in the carpet.
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Mosquitoes
The day-biting mosquitoes behind dengue and Zika. They breed in containers, and the eggs survive months on a dry rim.
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Mosquitoes
The malaria genus. It rests at a steep head-down angle rather than parallel to the surface.
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Mosquitoes
The West Nile virus mosquito. It breeds in stagnant, often dirty water rather than the clean containers Aedes wants.
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Mosquitoes
Three of the four life stages happen in water. Tipping out standing water is the cheapest control there is.
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Occasional Invaders
It does not live in your house, it hides there. It flew in last autumn and eats nothing all winter.
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Scorpions
"Scorpion" is not one species. Two species actually matter to a homeowner: the Arizona bark scorpion in the Southwest, and the striped bark scorpion in South Central Texas and neighboring states. They are different animals with different medical stakes. The Arizona bark scorpion is the only scorpion in the United States considered medically dangerous, and antivenom exists for severe cases, most often in children. The striped bark scorpion delivers a sting that hurts but is not dangerous to a healthy adult. Three more mild-venom Southwest species, the Arizona giant hairy scorpion, the Arizona stripe-tailed scorpion and the yellow ground scorpion, get misidentified as "the dangerous one" often enough that they are worth naming too.
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Spiders
Venomous, and far less dangerous than its reputation. The red hourglass is not always an hourglass and not always complete.
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Spiders
Six eyes in three pairs, not eight. The most misdiagnosed spider in America, and absent from most of it.
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Stinging Insects
The big black bee that charges your head cannot sting you. It bores round holes in bare wood to nest.
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Stinging Insects
"Wasp" is not one insect. The name covers paper wasps, yellowjackets, the bald-faced hornet, the European hornet and mud daubers, and they nest, sting and behave differently enough that getting the identification right decides what you should do next. One of them builds a colony of 15,000 that turns defensive in August. Another is a solitary spider hunter whose venom lacks the compounds that make a sting hurt.
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Termites
Termites that never touch soil. The first thing you see is six-sided fecal pellets, not the insect.
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Termites
Almost every termite page on the internet quotes the same annual damage figure. That figure traces to no primary source, not even in the university extension publications that print it. The best-sourced estimate is a 2012 review in Annual Review of Entomology by Rust and Su, which put the worldwide cost of termite control and repair near $40 billion a year, roughly half of that in the United States, with subterranean termites responsible for about 80 percent of it. That number was built backward from termiticide sales, multiplied by a repair-to-control ratio borrowed from Formosan termite work in New Orleans. Nobody has actually measured it. Treat it as an order of magnitude, not a measurement, and be skeptical of anyone who quotes you a damage total to the dollar.
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Termites
The super termite, and the nickname is earned. A colony can run about ten times larger than a native one.
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Termites
Near identical to the eastern subterranean termite. Same damage, same treatment, different half of the country.
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Ticks
The country's main carrier of Rocky Mountain spotted fever. Look for the mottled off-white shield behind the head.
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Ticks
The tick behind most Lyme disease in the Northeast. Adults are active October through May, not in summer.
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Ticks
The tick behind the red meat allergy. The female carries a single white dot, and it moves toward a host.
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Ticks
Arachnids, not insects. Tick season is not summer, and most people protect themselves for the wrong half of the year.
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Ticks
The West Coast Lyme carrier. It runs the opposite seasonal calendar from its better known eastern cousin.
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