Quoted By:
Well let's examine the BUGs more in-depth:
Butterfree is a butterfly, an insect.
Beedrill is a bee/wasp, an insect.
Paras/Parasect are most likely cycada nymphs infested by a fungus, so an insect.
Venonat might be a mite I think, which is an arachnid, Venomoth is, well, a moth, so an insect.
Pinsir is a stag beetle, so an insect.
Scyther is a praying mantis, so an insect, despite its reptilian features.
