From where Insects Come ?

There are a number of insects that exist as an adult for a very short period of time. Some beetles, just as an example, begin as an egg. The egg hatches and a grub comes out and it stays a grub underground for the rest of the summer and winter and following spring. Then it turns into a pupa and finally comes out of the ground next summer as an adult. The adults may live only long enough to mate and lay a new generation's eggs. I don't know what insect you have but I'll bet it's life cycle is similar to what I have described.