Arachnids, crustaceans, and insects do not contain blood but hemolymph instead. In the case of insects, hemolymph does not play an important role in oxygen transport. Some common uses are: creating a hydraulic system, autohemorrhaging, and gluing themselves to other animals. – WTF Fun Facts
Source: https://www.scientificamerican.com/article/how-is-bug-blood-differen/
