Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
LowBudget on Apr 23, 2014April 23rd, 2014, 2:27 am EDT
Many hardware stores will cut glass (or acrylic sheets) to size for you and sell you silicone caulk for the job. You may want to build a jig for assembly out of cardboard and tape to get the shape that you want. I have never seen one available commercially. It will off-gas while curing so you probably don't want to do it in a kitchen or bedroom.
Good luck
Ed
Ed
Low Budget Fly Tying and Fishing author of "Behind the Fly"
http://edengelman.com/BTF.html