Functions of blood:
a) Transport of minerals or food materials
b) Encapsulation: to protect from the large metazoan parasites, the haemocytes of blood, become aggregated around the foreign body forming a capsule of 2-3 layers. This leads to the death of the foreign bodies due to lack of O2 supply.
c) Phagocytosis:Engulf foreign material.
d) Immunity
e) Connective tissue formation
f) Wound healing or coagulation
g) Detoxification
h) Reflex bleeding: It is a phenomenon where emission of blood occurs through the pores or slits of the cuticle which mainly helps the insects for getting protection from their natural enemies.