Boreus coloradensis

There aren't many insects out and about during the last week of the year - at least not in North America. A little later on you can find small black stoneflies on the snow near mountain streams. A few spiders or midges might also be out. With persistence you might even find a wingless cankerworm or two but December is not known as the best time of the year to look for bugs. Of course you can easily find over-wintering beetles, caterpillars and bugs under rocks and logs but as far as active insects go, your chances are limited. Unless, that is, you're lucky enough to find a scorpionfly. Not any scorpionfly, mind you, but a small black scorpionfly that shows up on the snow much like a tiny piece of dislodged bark or a perhaps a chipped piece of stone. We happened to be just lucky enough a few weeks ago to find some.

These first two images are of small (3-5 mm long) snow scorpionflies of the family Boreidae. They don't look much like other scorpionflies that have colorful wings and lighter-colored bodies but the long rostrum is a bit of a giveaway. The first picture is of a female with her long ovipositor. The second picture is of a male. Erik, Michael and I found these over Christmas break in Rock Canyon above Provo (Utah). It was a bit of an overcast day but once we got into the canyon, the air cleared out and the snow was beautiful. Finding the boreids was a real bonus.

There aren't that many scorpionflies around to begin with - just over 500 species worldwide. Of these only about 30 belong to the family Boreidae, or the snow scorpionflies. Norm Penny is the leading authority on these remarkable insects. His world catalogue indicates that the only species known from Utah is B. coloradensis - so that's what I'm calling these individuals, at least for now. I was a bit surprised to discover that the little creatures can jump. They can't project themselves as far as fleas (which seem to be relatives of the Mecoptera) but they did manage to jump several inches when I approached them. That's a long jump for a creature with legs that are not much bigger than the commas on this page. And to imagine that all this activity (limited though it may be) is managed on a blanket of ice crystals.

I was surprised to find that John Acorn also has a nice image of another species (I think) on the last page of the American Entomologist (Winter 2010). I'm guessing that he found it in Canada but you'll have to ask him.

Bittacus chlorostigma

Hanging flies are unusual insects that often get overlooked. They aren't really flies at all. In fact they don't even look like flies. They are about an inch long and thin, and look a bit like large crane flies but they have four very obvious wings. Flies, of course (including crane flies), only have two wings.

Hanging flies are members of the Mecoptera, an order of insects commonly known as scorpion flies. This name is derived from certain species (in the genus Panorpa) where the males bear what looks like a stinger at the end of the abdomen. Hanging flies, however, do not have this threatening terminus and very often go undetected by even well-informed naturalists. This is unfortunate. They are fascinating insects to watch.


One easy way to tell them apart from crane flies or even damsel flies is to look at the head. Hanging flies (like most other mecopterans) have a pointed head. This picture is of Bittacus chlorostigma that I took earlier this year (in April) along the Merced River in California. It is a fairly common insect (if you know what to look for) in the spring throughout the open oak woodlands of the Sierra Nevada foothills. I have found them most commonly when the California poppies are in full bloom. This particular individual was out when a redbud was flowering a few feet away. The yellow spots (stigmata) at the end of the wings are very diagnostic, even if you can't get a good look at the head.


Hanging flies are best known for their unusual mating ritual where the males capture a prey item (usually a fly or small moth), hang from a small branch (or long blade of grass) with their forelegs, and then release a pheromone that attracts females. This is unusual among insects that use pheromones in that it is the male and not the female that sends the signal. Once a female finds the gift and accepts it, the insects couple. If the gift is too small the female looks elsewhere.


Most of the research that has been done on this interesting behavior comes from the Eastern and Midwestern species of Bittacus. The common California species (B. chlorostigma) is largely un-represented in these kinds of studies. A paper published in 1977 suggested that it was a nocturnal species because so little was known about it. This is certainly not true. I saw a pair exchanging gifts in April of last year above Pine Flat Reservoir. It was mid-morning and the pair was very approachable (unfortunately, I didn't have a good camera with me at the time). Some enterprising student might take this species on as a research project. They shouldn't be hard to find and they are quite attractive.