Problem:

My French friends inform me that these beasties are called cousins because they are "cousins" of mosquitoes (whatever that means).

The thing is, we are absolutely infested by them. They seem to be more active at dawn and dusk (like mosquitoes) but we have dozens flying around the house every evening. I would like to know the species' name to see if I can learn anything about them.

Required:

Question: Do they have cycles like cicadas?

Question: Are they linked to stagnant waters like mosquitoes?

Question: Why are there so many of them this year?

Please explain in detail.