It is bluish-green due to the presence of Hemocyanin, which is this color when oxygenated. Wyatt, G. R. (1961). The Biochemistry of Insect Hemolymph. Annual Review of Entomology. 6: 75–102. read more
The grasshoppers belong to an animal class known as Arthropoda. The blood of grasshoppers is known to be greenish or yellowish in colour. The circulatory medium of blood in grasshoppers does not contain red blood cells, which normally make the blood to be red in colour. read more