The length of the drosophila life cycle is temperature dependent - at 18 &#176; c it takes around 18 days for an egg to develop, pass through its larval stages, and emerge as a fly (enclosure).
(an egg; to develop; ) (an egg; to pass; through its larval stages) (an egg; to emerge; as a fly)
an egg an egg an egg
to develop to pass to emerge
through its larval stages
as a fly