They look like giant mosquitoes, and when I was a child, I was told by some well-meaning, but mis-informed adult, that a cranefly was a “male mosquito.” They do look like giant mosquitoes, and in fact, are in the same order: Diptera. All dipterans have only two flight wings. The second pair is reduce to a pair of knob-shaped “halters.” Craneflies are placed in their own family, the Tipulidae.

Craneflies are distributed across the wet regions of the world. They vary from as small as mosquito-size to the giants that we normally think of. The larvae are aquatic, and in the bigger species are often called “waterworms,.” These big larvae can be as long as 3 inches and nearly as big around as a person’s little finger. The body is a bit translucent, and the abdomen ends in a respiratory disk that at a casual glance might seem to be the head of the insect. The head is actually on the other end and quite small and retractable (that’s why most people never notice it).

These larvae live in an aquatic environment, from ponds, to wetlands, to lakes and rivers, and they occupy all sorts of substrate, from leaf pack to clean gravels. Many are a translucent dirty white, but others are olive, tan, dingy orange, and grayish. The larvae are well imitated by a furled imitation or one dubbed on a large, English bait hook. I tie these big imitations with plenty of weight so I can use them as an anchor fly when nymphing. Craig Matthews and John Juracek note in their book, Fly Patterns of Yellowstone that the big browns of the Madison seem to prefer a smaller version of their dirty-olive larval imitation, and fish it on sizes 8 and 10. One can still get a lot of weight into a fly of this size.

The larvae crawl out of the water and pupate in the wet stream bank. As a consequence, one never encounters an actual cranefly “hatch.” The smaller cranefly adults can occasionally be of importance to the angler, and they can be mimicked very well with an Adams. The big ones, however, produce some very interesting fishing. On rivers like Montana’s Bighorn, Madison, and Beaverhead, the adults can stir up the biggest fish. The females of the big species come back to lay eggs in the late evening, buzzing over the surface near shore, and often in significant numbers. Fish take them violently.

The best adult imitation that I have used is the Elk Hair Skater. The fishing tactic is rather unique, but highly effective. A big larvae is attached to a 1X or 2X tippet of about 2 feet in length. A tag end of 4 to 5 inches is allowed to remain where the tippet is attached to the leader. The big adult Skater is tied into this “dropper.” The imitations are cast down and across, and the rod tip lifted just enough to keep the Skater at the surface. The big larval imitation swings across underwater, while the dry slides along on top. By raising and lowering the rod tip just a bit, the fly fisher can cause the adult imitation to dance across the surface. It’s just too much for any self-respecting trout. Oh, by the way, stick with the 1X or 2X. When a 4 to 5 pound brown takes the dancing Skater, even 1X or 2X can seem foolishly light.

Watch for posts to come on tying the Furled Crane Larva, the dubbed Cranefly Larva, and the Elk Hair Skater.

Mating adult craneflies.


  1. Gary Eaton says:

    Professor Borger,

    I realize that your PhD in Biology gives you certain leeway in what is published. I wonder if you thought, for even a moment, how this type of “biologically insensitive” image might disrupt the morals of immature insects? Especially Crane Flies that could be overstimulated in a hormone-laden, carnal foray while accidentally viewing your blog!

    What’s next, innovative positions for reproducing crustaceans?

    Disgusting! Truly disgusting;-{o

    PS – Photographic quality remains quite good.

  2. Gary Borger says:

    Yes, Dr. Eaton, there was much discussion at the table regarding the image–to post or not to post, that is always the question. But in the end,it was felt that younger craneflies need to know where they came from and where they are headed. The image was made with the consent of both members of the mating pair. Some days, one has to tackle the tough questions in life, regardless of the overall impact on the cranefly population. I know the image was hard for you to look at; or perhaps too inviting?

    For those that don’t know, Gary and I are good friends and this exchange is totally in good-natured fun.

  3. JB says:

    So NOW you tell me about the birds and the dipterans…. ;)