Contraband Rocket — Murray Leinster

THE FORGOTTEN PLANET is a world where the Terraforming stopped too soon. Result: insects evolved to human size plus. Non-chlorophyll plants also prospered and killed off the trees and grasses, then evolved into hugeness themselves. You would not expect a shipload of people stranded on such a world to survive, but humans are stubborn and resourceful. This is the story of their many-times descendants, and it's a great one.