Caleb is a forensic entomologist gathering evidence at a crime scene. How can he determine the stage the maggot larva has reached? Caleb is a forensic entomologist gathering evidence at a crime scene. From the victim's mouth, he retrieves maggots that are in the

which is the stage maggots reach directly after hatching. He can determine the stage of the maggot larva based on the

and the

of the larva.