Use the parameter
maxHops to specify the depth of your crawl from your seed URL(s). A value of 0 will limit crawling only to your seed(s).
maxHops=1 will spider all links from your seed URL(s);
maxHops=2 will follow the links on those pages; etc.
maxHops setting of -1 (default) will spider all links at any depth.
This can be used in conjunction with URL crawl patterns to more finely-tune your crawl.