Why did the wasps lay the eggs in the aphids?

Question: Why did the wasps lay the eggs in the aphids?
- Keywords:
  aphid,
  egg,
  wasp
Asked by to Woody, Natasha on 15 Jan 2018. This question was also asked by .
- Woody Clarke answered on 15 Jan 2018:
  
  From my understanding, this species of parasitic wasp must lay eggs an aphid to finish it’s life cycle. The injected egg form into a larvae and feeds of its host! (eating it alive!) it grows several times its size until the aphid dies, then it can become a wasp.

Question: Why did the wasps lay the eggs in the aphids?