>>58161955
>>58161977
That leads more credence to my theory that someone else implemented Butterfree afterwards rather than belonging to Venonat. If Venonat was designed to be related to Butterfree instead of Caterpie, it wouldn't be following Caterpie in the index. Someone suggested the sprites were swapped but that makes even less sense than just swapping the entire bank relation because that's what they ended up doing for most mons to begin with.

>>58161958
>Who is Beedrill
There aren't many Bug mons to argue this point to begin with. By Gen II they would've outright changed their design philosophy so trying to use future reference doesn't work in this instance. The only Bugs in Gen I are the Caterpie, Weedle, Venonat, Paras lines and Pinsir/Scyther, the latter of which was one of the first Pokemon designed and was retrofitted to look like a bug

>>58161988
The order is incredibly clear-cut. Venonat was designed EARLY while these Bugs were designed much later after they started implementing "types". Basically BP and AP (Before Pikachu/After Pikachu)