 Why were the Sirian spiders rejected for the travel plan?
The aliens came in every shape and form, in all colors and textures—and all of them eager for a Corrigan contract. Before then, anyone could visit Earth. At the same time, we had turned away a dozen ursinoids, fifty of the reptilian natives of Ghryne, seven Sirian spiders, and no less than nineteen chlorine-breathing Procyonites wearing gas masks. I had turned away three more ursinoids, hired a vegetable from Miazan, and said no to a scaly pseudo-armadillo from one of the Delta Worlds. And now, please, there are many applicants waiting—" You'd think it would be sort of humiliating to become a specimen in a zoo, but most of these races take it as an honor.
 They had an over-supply of their species.
 They demanded too high of payment.  They had an over-supply of their species.  They all expected a handout  They were difficult to work with.