The Crystal City(1985)
(The second book in the The Watchers of Space series)
A novel by Nancy Etchemendy
When they accidently encounter intelligent giant spider beasts during a copperdust storm, William and Maggie must convince the skeptical leaders of the New Genesis colony of the aliens peaceful nature.
Used availability for Nancy Etchemendy's The Crystal City
August 1985 : USA Paperback