1. Crustaceans
Crustaceans are a type of Arthropod. The name may not sound familiar, but you probably know them. You may even have eaten one.
Crustaceans live mostly in the ocean or other waters. Most commonly known crustaceans are the crab, lobster and barnacle.

2. Arachnids
Arachnids are a type of arthropod. You know many of them as spiders.
Like other arthropods, the arachnids have a hard exoskeleton and jointed appendages for walking. Unlike other arthropods, arachnids do not have antennae.
Common arachnids are the spider, scorpions, ticks and mites

3. Insects
Insects are the largest group of arthropods. There are over 800,000 different types of insects. Insects are very adaptable, living almost everywhere in the world. Insects have an exoskeleton that covers their entire body. An insect's body consists of the head, thorax and abdomen

4. Millipedes
: It isn't unusual for people to refer to millipedes as "wireworms". In fact "wireworms" is a term commonly used by local residents when they are referring to millipedes. If you need to choose a control option for one of these pests, it is important to know which pest you really have!
Millipedes are sometimes called "thousand-legged worms" because of their many legs (photo above).
Wireworms (photo below) are the larval stage of a beetle. They have only six legs and those are located near the head.

5. Centipedes This a garden centipede…
Centipedes and millipedes are not insects because they have more than six legs, but they are closely related invertebrates. When outdoors, these invertebrates are innocuous organisms, but they may be considered pests when they share living space with us. Both of these groups of invertebrates have long, segmented bodies with either one pair (centipedes) or two pairs (millipedes) of legs on each segment. Their food preferences vary greatly. 

6. Horseshoe Crabs living Fossils
1. This is a crab that isn't a crab!  It is distantly related to spiders and scorpions.  To avoid confusion, let's call it by its correct name, Limulus polyphemus. (Pronounced Lim-u-lus poly-feem-us)
2. The Limulus is a "living fossil" whose origin dates back to Triassic times, over 200 million years ago, a time when the first dinosaurs and primitive mammals appeared.  Few other well-known animals can claim that record.  It is not easy to be a living fossil.  To apply for this category, that animal can only have, at most, a few close relatives.  The body form should not have changed over the years.  A true living fossil's family tree must be tens, or preferably hundreds, of millions of years old.