Rightly, a dream about dead butterflies or dead bugs like this should be treated with equal gravity and not thrown aside. The butterfly is not a bug that people generally swat at or attempt to kill because of how delicate it is, making this interpretation all the more important.
Dead butterflies are known for being a tough dream symbol because of the fact that people have such strong connections to butterflies. Many people love butterflies because they are so delicate and seemingly innocent. People see them as beautiful and they are something of a hero story because even though they come from something as ugly and strange as a caterpillar, they can still turn out to be quite attractive and not weird at all at the end of it all.
Butterflies are also seen as a great thing because they are known for getting rid of menacing creatures and all of those annoying other pesky creatures. Their wings are so pretty they help to add a bit of joy to what might otherwise be considered a pretty sad looking garden. If you have a dream about the death of a butterfly though then this might mean that you were not able to adequately appreciate the butterfly that you did see in your dreams earlier. If you have a dream in which you see a dead butterfly it can mean some pretty bad things, it can mean that you have a more hardened and pessimistic view of the world. Butterflies are known for being seen as delicate or innocent. When they are dead then it must seem like there is nothing delicate or innocent in the world at all anymore which can be absolutely devastating.