Here's a list of the insects you can find in Animal Crossing: New Leaf. You can bring new bugs to the museum, sell them to get bells, and they can also be displayed in your home inside a cage. Note that you'll find different bugs at different times of the day and locations.

Also, don't forget to visit the island as soon and as often as you can, as it's amazing how many special creatures you'll find there, especially beetles and stags. Once they're in your museum collection, sell them for crazy loads of cash (I come back from the island every night with 150,000-200,000 bells)! The bug names you see with an asterisk (*) are additions to AC New Leaf.
Where you can you find bugs in Animal Crossing: New Leaf?
Plants, trees, tree stumps, under a rock, in the air, underground, on the water, and even inside rotten fruit!
AC: New Leaf Bug List
Picture
Bug Name
Location
Spawning Chance
Months
Times Available
Re-Tail Price

Agrias Butterfly
Air / Island
3%
Jun. - Sep.
8 a.m. - 5 p.m.
3,000

Ant
Rotten Food
15%
All Year
All Day
80

Bagworm
Shaken Trees
4%
Oct. - Feb.
All Day
300

Banded Dragonfly
Near Ponds / River
3%
Jul. - Aug.
8 a.m. - 5 p.m.
4,500

Bee
Shaken Trees
N/A
All Year
All Day
2,500

Bell Cricket
Ground
N/A
Sep. - Oct.
5 p.m. - 8 a.m.
1,720

Birdwing Butterfly
Flowers / Island
2%
Jun. - Sep.
8 a.m. - 4 p.m.
4,000

Brown Cicada
Trees
15%
Jul. - Aug.
8 a.m. - 5 p.m.
200

Common Butterfly
Air
25%
Mar. - Jun.;
Sep.
4a -7 p.m.
90

Centipede
Hit Rocks
8%
Jan. - Feb.
4? - 11 p.m.
300

Cicada Shell*
Trees
N/A
Jul. - Aug.
All Day
100

Cricket
Ground
N/A
Sep. - Nov.
5 p.m. - 8 a.m.
160

Cyclommatus Stag
Palm Trees/ Island
4%
Jun. - Aug.
5 p.m. - 8 a.m.
8,000

Darner Dragonfly
Air
11%
Jun. - Aug.
8 a.m. - 5 p.m.
200

Diving Beetle
River / Pond
5%
May - Sep.
8 a.m. - 5 p.m.
800

Dung Beetle
Snowballs
9%
Dec. - Feb.
5 p.m. - 8 a.m.
800

Emperor Butterfly
Flowers/ Island
11%
Jun. - Sep.
7 p.m. - 8 a.m.
2,500

Evening Cicada
Trees
17%
Jul. - Aug.
5 p.m. - 7 p.m.
550

Firefly
Near Ponds / River
23%
Jun.
7 p.m. - 4 a.m.
300

Flea
Villagers
4%
Mar. - Nov.
All Day
70

Fly
Rotten Turnips /
Trash
33%
All Year
All Day
60

Fruit Beetle
Island / Trees
23%
Jul. - Aug.
Sep.
All Day
7 p.m. - 8 a.m.
100

Giant Cicada*
Trees
N/A
Jul. - Aug.
8 a.m. - 5 p.m.
500

Giant Stag
Island / Trees
2%
Jul. - Aug.
11 p.m. - 8 a.m.
10,000

Golden Stag
Palm Trees / Island
2%
Jun.- Aug.
5 p.m. - 8 a.m.
12,000

Grasshopper
Ground / Island
9%
Jul. - Sep.
8 a.m. - 5 p.m.
160

Goliath Beetle
Palm Trees / Island
5%
Jun. - Sep.
7 p.m. - 8 a.m.
6,000

Horned Atlas
Palm Trees / Island
3%
Jun. - Aug.
5 p.m. - 8 a.m.
8,000

Horned Dynastid
Island / Trees
8%
Jun. - Aug.
7 p.m. - 8 a.m.
1,350

Horned Elephant
Palm Trees / Island
3%
Jun. - Aug.
5 p.m. - 8 a.m.
8,000

Horned Hercules
Palm Trees / Island
1%
Jun. - Aug.
5 p.m. - 8 a.m.
12,000

Hermit Crab*
Island / Beach
14%
All Year
7p.m. - 8 a.m.
1,000

Honeybee
Flowers
10%
Mar. - Jul.
8 a.m. - 5 p.m.
100

House Centipede*
Hit Rocks
N/A
Aug. - Oct.
7 p.m. - 8 a.m.
250

Jewel Beetle
Island / Trees
6%
Jul. - Aug.
8 a.m. - 5 p.m.
2,400

Lady Bug
Flowers
10%
Mar. - Jun.;
Oct.
8 a.m. - 5 p.m.
200

Lantern Fly
Island / Trees
6%
Jun. - Sep.
4 p.m. - 8 a.m.
1,800

Locust
Ground
N/A
Aug. - Nov.
8 a.m. - 7 p.m.
400

Longhorn Beetle
Stumps / Island
7%
Jul. - Aug.
11 p.m. - 6p.m.
260

Long Locust
Ground / Island
9%
May - Nov.
8 a.m. - 7p.m.
200

Mantis
Flowers
6%
Apr. - Nov.
8 a.m. - 5 p.m.
430

Migratory Locust
Ground / Island
6%
Aug. - Nov.
8 a.m. - 7p.m.
600

Miyama Stag
Island / Trees
6%
Jul. - Aug.
All Day
1,000

Mole Cricket
Underground
12%
Nov. - May
All Day
280

Monarch Butterfly
Air by Flowers / Island
12%
Jul. - Nov.
9 a.m. - 5 p.m.
140

Mosquito
Air
10%
Jun. - Sep.
5 p.m. - 4 a.m.
130

Moth
Near Lights / Island
17%
May - Sep.
7 p.m. - 4 a.m.
60

Oak Silk Moth
Island / Trees
5%
Jun. - Sep.
7 p.m. - 4 a.m.
1,200

Orchid Mantis
White Flowers / Island
4%
Apr. - Nov.
8 a.m. - 7 p.m.
2,400

Peacock Butterfly
Flowers - Blue, Black, Purple / Island
10%
Mar. - Sep.
4 a.m. - 7 p.m.
220

Petaltail Dragonfly
Air
3%
(COMMON ON
TOURS)
Aug. - Oct.
5 p.m. - 7 p.m.
8,000

Pill Bug
Hit Rocks
13%
All Year
All Day
250

Pondskater
Ponds
6%
May - Sep.
8 a.m. - 7 p.m.
130

Rainbow Stag
Trees
3%
Jun. - Sep.
5 p.m. - 8 a.m.
10,000

Raja Brooke Butterfly
Air by Rivers
3%
May - Sep.
8 a.m. - 5 p.m.
2,500

Red Dragonfly
Air
19%
Sep. - Oct.
8 a.m. - 7 p.m.
80

Rice Grasshopper*
Ground
N/A
N/A
8 a.m. - 5 p.m.
300

Robust Cicada
Trees
13%
Jul. - Aug.
8 a.m. - 5 p.m.
300

Saw Stag
Trees / Island
4%
Jul. - Aug.
All Day
2,000

Scarab Beetle
Trees / Island
2%
Jun. - Sep.
11 p.m. - 8 a.m.
6,000

Scorpion
Ground
1%
Jul. - Sep.
7 p.m. - 4 a.m.
8,000

Snail
Shrubs (rainy day)
N/A
Apr. - Sep.
All Day
250

Stinkbug*
Trees
N/A
Apr. - Oct.
All Day
120

Spider
Shaken Trees
N/A
Mar. - Oct.
All Day
300

Tarantula
Ground
1%
Jun. - Aug.
4 a.m. - 7 p.m.
8,000

Tiger Beetle*
Ground
8%
Mar. - Oct.
8a - 5p / 4p - 11p
1,500

Tiger Butterfly
Red Flowers / Island
8%
Mar. - Sep.
4 a.m. - 7 p.m.
160

Violin Beetle
Stump
N/A
Jun. - Nov.
4 a.m. - 7 p.m.
260

Walker Cicada
Trees
9%
Jul. - Sep.
8 a.m. - 5 p.m.
400

Walking Leaf
Ground near trees (looks like furniture)
4%
Jul. - Sep.
8 a.m. - 5 p.m.
600

Walking Stick
Trees / Island
7%
Jul. - Nov.
4 a.m. - 7 p.m.
600

Wharf Roach*
Beach Trees / Island
21%
All Year
All Day
200

Yellow Butterfly
Flowers
21%
Mar. - Jun.; Sep.
6 p.m. - 4 a.m.
90