I know I can do that. I did it right after I read your first reply, to see what kinds of fireflies were out there, but I canceled it after that. At that time, there were only the same yellow and green ones she'd already found. There have been two more nights in her game since then, and I have used the collection helper to check on the insects while she's sleeping. So far, she now has collected a purple one, a roseus one, and a white one (albus). That makes 5 kinds so far. She really only still needs the blue one now, for the elixir. I might give her the opportunity some other night, if I don't find any blue ones in the next few of sim nights. But I'm playing this game with no cheating, except what is necessary to fix glitches, so I'm going to avoid giving her the opportunity unless it turns out to be the only way she can get that blue firefly.
By the way, thank you for your help.