"for, like Hudibras, he wore but one spur "

Hudibras is an English mock heroic narrative poem written by Samuel Butler in the 17th century.  The quote refers to the following verse:

Western-style cowboy spurs
Public DomainWestern-style cowboy spurs - Credit: Cowboy Wisdom
His draggling tail hung in the dirt,

Which on his rider he would flirt

Still as his tender side he pricked

With armed heel, or with unarmed, kicked:

For Hudibras wore but one spur,

As wisely knowing could he stir

To active trot one side of's horse,

The other would not hang an arse.