Sentence:  When she succeeds , she usually manages to slip in unobtrusively , to deposit an egg on a completed loaf of beebread before the bumblebees seal the <WSD>egg</WSD> compartment . 
Meaning of the word marked with <WSD> tags:  animal reproductive body consisting of an ovum or embryo together with nutritive and protective envelopes; especially the thin-shelled reproductive body laid by e.g. female birds