Planet of Origin: Supposedly in planet orbiting Betelgeuse
The Crabmen are a vaguely humanoid crustacean species that developed a spacefaring civilisation as of the 4th millenium. They possess large pincer-like hands and antennas that can spew a deadly green acid and had a geometric language.
Source: Beyond Infinity, by Nat Schachner Aka Chan Corbett, in Astounding Stories, Jan 1937.
The story tells of a series of invasion that befell Earth starting in 3195, as the universe unexpectedly starts to collapse on itself and the surviving species rush toward the worlds who are still unaffected by the phenomenon to delay their extinction. The Betelgeusians were the second of a wave of invaders that attacked Earth, arriving in 3241, as a migration fleet of 100 000 spaceships fleeing their homeworld's destruction. They were defeated by mold and spores which attacked the softr skin under their shells. They nevertheless reduces the Earth population to 2 billions people.