The diddley bow is of African-American origin, probably developed from instruments found on the Ghana coast of west Africa.  The diddley bow is rarely heard outside the rural south.  Other nicknames for this instrument include “jitterbug” or “one-string,” while an ethnomusicologist would formally call it a “monochord zither.”  The diddley bow has traditionally been considered an "entry-level" instrument, normally played by adolescent boys, who then graduate to a "normal" guitar if they show promise on the diddley bow.  Many famous blues guitarists started out on a diddley bow, but because it was considered a children's instrument, very few musicians continued to play the diddley bow once they reached adulthood.  The diddley bow is therefore not well represented in recordings.   As of this writing, the commercially available recordings of traditional diddley bow players might fill two CDs, but would not fill three.