The Differences and Similarities Between Bugs vs Insects

Remembering studying the different classes of animals back in high school science class, usually a biology class? Bug vs insect was usually a question a kid or two had in class, and it’s a legitimate question with a very clear set of answers to tell the difference between bugs vs insects, neither of which has eight legs. 

Bugs vs. Insects – What’s the difference?

So the term bug refers to the order Hemiptera, which is under the class of Insecta, therefore, bugs are insects, or rather, a type of insect, and have six legs and two antennae. But, that doesn’t mean that all insect are bugs

Bugs have:

  • strong little pairs of wings (the smaller front wings are usually harder)
  • two sets of wings (one small pair and a large pair of hind wings)
  • piercing mouthparts that more resemble that of a straw.
  • three segmented body parts
  • three pairs of legs, so that’s a wide variety of insects that fall under the category of “bug”

flies insectThink of mosquitos and flies – those are bugs, but they are also insects. 

Most type of insect have wings, but that does not mean that they can fly. Most insects go through different life stages and undergo significant biological changes before getting their set of wings. 

What does the dictionary tell us about true bugs?

The technical definition of bugs is that bugs are defined as small insects that have a mouthpiece designed to suck juices for their food. Insects called Hemiptera are considered true bugs, so the word bug applies so the creepy crawlies under the umbrella of Hemiptera

Interestingly enough, some insects such as ladybugs are not actually bugs, they are beetles, and the lovebug is actually a fly

true bug stink bugTrue bugs are more like mosquitoes, flies, aphids, and even some non-insect Arachnids. One true bug with bug in its name are the stink bugs, meanwhile water bugs are actually a type of cockroach

Are centipedes insects?

Technically, no, they are Arthopods, and are more closely related to crabs, spiders, and sea horses than they are to insects and bugs. Insects are right under Arthropods so all insects are actually Arthropods, but not all Arthropods are insects. 

Are spiders insects?

No, spiders are not from the class Insecta, they from a class called Arachnida which is as different as saying dolphins are different than monkeys. 

Not all insects can fly

Insects such as fleas, bed bugs, and lice do not actually have wings, while there are other insects, like cockroaches, that have wings, but are truly flightless. 


Bugs are defined as the order Hemiptera, so if you really want to know if an insect is a bug, check its class!

Common usage of the word “bug” in a name doesn’t mean that the insect is actually a bug. So don’t be fooled by “ladybugs” being classified as bugs.

Not all insects have wings. Even some that do have wings can’t even fly, so you can’t go by that definition alone either. Instead, pay closer attention to the number of legs as that is a far clearer judge of animal.

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