As soon as the big black lake bibios are hatching, do not waste time with other types of flies and immediately tie some fly pattern from our offer. Fish loves this type of insect and feed it masively when it comes to its abundant occurrence. Bibios are large terrestrial insects and often occur on larger natural lakes or on rivers with dense coastal vegetation. Their appearance is unmistakable, so you will immediately know when the trout feed them when the big black flies fly over the surface. Do not underestimate their meaning and have some Hawthorn patterns in your fly box!