A butterfly net (sometimes called an aerial insect net) is one of several kinds of nets used to collect insects. The entire bag of the net is generally constructed from a lightweight mesh to minimize damage to delicate butterfly wings.
Nigel Marven tried to use a big butterfly net to catch a Meganeura but not only did a Crassigyrinus bite him, but the net is clumsy and he failed many times. So he uses an 8 foot water gun filled with detergent. He finally gets a Meganeura with the gun and catches it with the net.