Digests chitin in the exoskeleton during the molting process. Random endo-hydrolysis of N-acetyl-beta-D-glucosaminide (1->4)-beta-linkages in chitin and chitodextrins. Epidermis and gut. High levels seen in the epidermis on day 0, but rapidly disappears and is undetected on days 1-4 of fifth instar. It reappears on day 5 and peaks on day 7 after which a rapid decline is seen. In the gut is detected on day 6 with lower levels seen on days 0, 7 and 8. Belongs to the glycosyl hydrolase 18 family. Chitinase class II subfamily.