How do tachinid flies develop within monarch larvae?

Female La (Lespesia archippivora) lay eggs on the host integument (skin), and the fly larvae hatch and bore into the host soon after oviposition. La complete their larval development within the host, the maggots emerge from late larvae or pupae, and then pupate in leaf litter and eclose within about 10-14 days. Fly maggots drop to the ground on long, gelatinous tendrils that look like white strings hanging from the monarch.