Captain has specially assigned you a special net that will catch and remove the fireflies if you get them in there. The goal is to catch the queen, but she's hard to find, hiding and only glowing out of the shadows on occasion. Our intelligence says the more of her children you capture (the orange ones) the more likely she is to show herself. Take out however many you need to discover and capture her.
Beware though! You don't want to lose any of our own, so avoid catching the other butterflies at all costs.