Each Uncommon insect, that you catch for a second time is worth twenty dollars (bucks, Pounds, Yen, or Euro). These bugs are as numbered:

5. Uncommon Pale Moth
6. Uncommon Lapis Butterfly
7. Uncommon Lemon Moth
17. Uncommon Hiding Beetle
18. Uncommon Zebra Beetle
19. Uncommon Cockroach
29. Uncommon Dart Dragonfly
30. Uncommon Fragile Dragonfly
31. Uncommon Ghost Dragonfly
41. Uncommon Pearly Spider
42. Uncommon Limelike Spider
44. Uncommon Cricket Spider