12: Butterfree 14: Kakuna

Weedle

13: Weedle

Kanto

	HeartGold	SoulSilver	FireRed	LeafGreen	Crystal	Gold	Silver	Yellow	Red	Blue
Walking in tall grass or a cave
Pattern Bush			10% L6	10% L6
Route 2 north, towards Pewter City		1% L4 +20% L3 +10% L3 +10% L3 +10% L5
Route 2 south, towards Viridian City		1% L4 +20% L3 +10% L3 +10% L3 +10% L5	5% L4–5	5% L4–5			+30% L3 +30% L3		15% L3–5
Route 24			20% L7	20% L7					20% L7
Route 25			20% L8	20% L8					20% L8	1% L8
Viridian Forest		+40% L3 +40% L3	40% L3–5	40% L3–5					45% L3–5	5% L3

Johto

	HeartGold	SoulSilver	Crystal	Gold	Silver
Walking in tall grass or a cave
Ilex Forest		+20% L5 +40% L5–6 +30% L5–6 +10% L5 +10% L6	+30% L5 +30% L5		+50% L5 +60% L5–6
National Park		+20% L10 +20% L10 +30% L10–12 +10% L10	+5% L10 +5% L10		+50% L10–12 +30% L10
Route 30		+20% L3 +25% L3–4 +30% L3–4 +10% L3	+5% L3 +5% L3		+50% L3–4 +35% L3–4
Route 31		+20% L4 +25% L4–5 +10% L4 +10% L4	+5% L4 +5% L4		+30% L4 +35% L4–5
Unknown; all bugs		100% L10–14

Sinnoh

	Platinum	Diamond	Pearl
Walking in tall grass or a cave
Eterna Forest	+4% L13
Route 204 north, towards Floaroma Town	+8% L10
Route 204 south, towards Jubilife City	+8% L5	+8% L6	+8% L6

Kalos

	X	Y
Walking in tall grass or a cave
Route 2	11% L3–4
Santalune Forest	20% L2–3	10% L2