A rather large and colorful fly landed in dappled light on the Buford trail recently. At first I thought it was a midge, because midges hold their front legs in front of them like they’re getting ready to dive. But after more research, I’ve discovered it’s an awl fly. 

An awl is a tool that makes holes in wood. And this insect’s scientific name, Xylophagus, is Latin for “wood eating.” So it makes sense that this Xylophagus genus awl fly is a wood-borer as a larva. As an adult, it may be a pollinator. 

Photos of the larvae show a cream-colored grub with a black, tapered, and weirdly pointed head. Larvae are predators, and according to one research paper I found, they use their tool-shaped noggins and “sickle-like mandibles” to tear open and eat their prey, which is both the larvae and pupae of other insects.  

As is true for many insects, not much is known about this fly’s day-to-day lifestyle and habits. The study I mentioned earlier cites a 1961 paper saying the larvae live for three years in the dark confines under tree bark, before pupating and becoming adults. The authors note that in 1972, another set of researchers said the larvae lived just one year, but the evidence they used was “anecdotal.”

The BugGuide.net website says the female’s eyes are spaced apart, and males are touching. And they say the female’s abdomen is plump and tapered, and that it extends beyond the wings. The overhead view here is of another fly I found at Mount Pisgah, and it certainly looks like a female. 

Stay curious!

See more of Karen’s work here.


Research paper on Xylophagus cinctushttps://www.jstor.org/stable/25085652. Accessed 6/7/23.

Photos of the larvae, looking like awls: http://soldierflies.brc.ac.uk/early-stages/xylophagidae. Accessed 6/7/23.