1)Animals have jointed appendages .
2)Exoskeleton is present which is made of chitin.
3)Circulatory system is open, which means blood flows in the coelomic cavity.
4)This is the largest group of animals; in terms of number of species.
5)They breathe through trachea
6)They are bilaterally symmetrical
7)They are triploblastic organisms
8)Examples are honeybee,spider etc
Thats why cockroaches are included in arthropoda