I'm trying to remember the title/author of a book from perhaps the 1970s. In it, some kind of astronomical disaster has destroyed the earth, and a few shiploads of people have escaped to a different solar system, populated by butterfly people. The same disaster will hit there in a decade. Together, the humans and butterfly people figure out a better kind of starship, which they can use together to save a small number of people. But the humans double-cross the butterfly people, and steal all the starships. Except then the butterfly people triple cross the humans, and blow up all the starships, so everyone dies.
Anyone know it?
Anyone know it?
