Please help to identify this maggots like pest

[bear88hunter]

Hi all, I am living in Sydney Australia. My crucifix are eaten by the attached pests. They seems to eat the crucifix only and not other orchids. Their bodies are very soft and jelly like. I think the body maybe translucent as their colour change depend on what colour of flowers they eat. It is orange with the orange crucifix and purple with the purple flowers. The biggest I've seen is around 10mm. I use google to search but the closest answer is maggot which I doubt. They seems to emerge when the sun comes back after raining a few days. Just wonder what they are and how to get rid of them.

Many thanks
Francis