Ticks are commonly referred to as insects, but they are technically arachnids because they have eight legs. As larvae, however, they have six legs.
One key to tick identification is the scutum, or shield, which covers part of the tick's back. A deer tick has a solid colored scutum but other species will have patterns. The scutum of the tick can also identify the sex of the tick. A female tick has a smaller scutum while the male has a larger one.
The mouthpart, or capitulum, is another way of identifying the sex of a tick. For example, a female deer tick has a larger capitulum than a male deer tick because male deer ticks don’t feed.
Ticks are easier to identify once they are done feeding because their body becomes engorged. The scutum remains the same size, but the body will become larger and change color once feeding is complete. The colors range from brownish red to pale gray or greenish grey.