I don't see what else it could be aside from thrips. They do have yellow larvae, and thrips are frequently found in flowers because pollen is their favorite food. Here are some pictures I took of the larvae and adults at work not long ago. These are seen under a binocular microscope, so actual size is 1-2mm. The silvering is caused by the adults feeding by sucking the plant cells dry.
These should be dealt with quickly as they are an important vector of many viruses.
I'm actually doing research on thrips for my Bsc thesis, so I see these little bugs everyday!

I'm starting to really hate them!!
Hope this helps!