Chitin is the main component in this supportive outer covering of lobsters & insects
... such as the 
decapods (10 legs), including crabs and lobsters, or the arachnids (8 walking 
legs), ... Insects have the traits already discussed for the arthropods and the 
mandibulates - exoskeleton (of chitin, a light material but very supportive if a 
structure is small... [DOC] [TLE] The Exoskeleton - NC State University [PAR] Feb 17, 2006 ... An insect's exoskeleton (integument) serves not only as a protective covering ...