Kago
From A complete guide to Super Metroid speedrunning
Although you can hit the kago to get the bugs to come out, this is only referring to the actual kago itself, not the bugs. The inner portion is actually vulnerable to a few things, including bombs. So, if you laid 4 power bombs on the kago and they all damaged twice then it would die with only one drop. The bugs themselves are technically not considered enemies, but projectiles, so they aren't on the enemies page.
It's possible to fall through the kago with a technique called kagoing.