The history of intermediate wraps harkens back to the days when rods were made using hide glue which was not waterproof. Then, intermediate wraps were used as “insurance” to prevent the sections, or strips, from coming apart. Today’s glues render intermediates to be mostly cosmetic on solid built fly rods for that purpose alone. Today, intermediates are sometimes used to stiffen rod sections a bit and compliment a rod design to achieve a desired action.
On hollowed rods, I sometimes will use intermediates to increase it’s resistance to “hoop” stress lending additional strength to the hollowed blank. A full dress bamboo fly rod is a thing of beauty to behold and is very distinctive on the stream.
Intermediate wrap coupled with a swelled mortised butt using snakewood inserts.