How did you catch a Monarch Butterfly when it isn't supposed to be available yet?
Alright, here's the inforation from GameFAQs on the ones you still need:
[Peacock Butterfly]* Karasuageha - 220 - C - yellow - 105mm - near blue, purple
and black flowers - March through June, 4am to 7pm (best time is 8am to 5pm,
May through June) - July through August, 8am to 5pm - September, 8am to 4pm
[Bee]** Hachi - 2,500 - B - red - 38mm - in trees - all year, all day
[Migratory Locust]* Tonosamabatta - 600 - D - yellow - 58mm - on ground -
August through November, 8am to 7pm (best time is 8am to 4pm)
[Red Dragonfly]* Akiakane - 80 - D - green - 38mm - in air - September through
October, 8am to 7pm (best time is 4pm to 5pm)
[Banded Dragonfly]* Oniyanma - 4,500 - B - yellow - 90mm - in air - July
through August, 8am to 5pm
[Giant Petaltail]* Teioumukashianma - 8,000 - A - red - 160mm - in air - August
through October, 5pm to 7pm
[Cricket]* Koorogi - 130 - E - wood - 28mm - on ground - September through
November, 5pm to 8am
[Bell Cricket]* Suzumushi - 430 - D - wood - 18mm - on ground - September
through October, 5pm to 8am
[Bagworm]** Minomushi - 300 - D - purple - 50mm - in trees - October through
February, all day (best time is November through December, 8am to 7pm)
[Dung Beetle]** Funkorogashi - 800 - B - yellow - 35mm - near snowballs -
December through February, 5pm to 8am
[Fly]** Hae - 60 - E - green - 9mm - near garbage, rafflesia or spoiled turnips
- all year, all day
[Scorpion]* ** Sasori - 8,000 - B - red - 160mm - on ground - July through
September, 7pm to 4am
*Does not appear during rain.
**Does not appear when the gate is open.