I believe the critters you are talking about are mayfly nymphs. We use them for perch on mud flats and they often out-produce waxies or spikes(but not always). Heres the rub, they are a pain to transport as you get them in a little styro cup, you either break the cup or they freeze solid half way into the trip. To hook them on you let them sit upright on your finger and run the hook from tail to head so that the point comes out just behind their "body section" or the section of thier body that is right behind the head. hook them shallow and they live for a fair amount of time, in most cases they swim so hard you can see it on your rodtip.