This is how it went:
1st one-WOW! I caught a mosquito! I caught a mosquito! I'm so excited!
2nd-Whoa! I caught another one! I'm so lucky! I actually caught another one!
1000th one:Dang it, mosquito, get out of my way so I can catch this other bug!
So I assume mosquitoes launched the 28th of May, and now there is nothing rare about them.
Meanwhile I still need a banana slug, and evidently my town is in the middle of the desert. No rain, no slug. No worm, either.