A small delicate fly, about the size and shape of a mosquito, drifts in from the porch door into the kitchen. I stifle the impulse to swat it--it's a reflex, an unconscious motion that many of us succumb to, to smash a flying insect. But mosquitoes are so rare in December in Boston that if I saw one it would be better to catch it and identify it for novelty's sake if nothing else.
You can see by the way this fly stands on the wall, all six legs down, that it is not a mosquito. Most mosquitoes land head down, back end up, with the last two legs off the surface--all the better to take a quick drink of you. To that point look at the fly's head: no proboscis.
This harmless visitor is a winter crane fly Trichocera
sp. It is active in the warmer parts of the colder months, an adaptation that allows it to avoid predators. Their larvae are little white maggots that chew their way through compost and manure and wet vegetation, benefitting from habitat concentrated around humans such as leaf piles, rodent burrows, and even stored root vegetables.
One of my favorite things about crane flies is how their halteres are big enough and exposed enough to be visible to the naked eye.