Wednesday, July 14, 2010

Tachinid Fly

 This large fly is called a Tachinid Fly in the genus Archytas and family Tachinidae. These are large, hairy flies that typically nectar at flowers. Right now my peppermint is in full bloom and it is covered in these enormous flies. There are easily 50 or more nectaring at a time.
These flies start their life out as parasitoids of other insects such as moth caterpillars. The unfortunate host will not survive such an onslaught by the vigorous eating habits of the maggot of these large flies.

These flies do not spread disease to humans, or contaminate food, or eat poo for that matter. Overall these flies have very good manners. Some of them reach enormous sizes...I have a few that are almost 3/4 of an inch in length, maybe larger. They are very thick bodied and covered in bristly hairs.

Males will have eyes that nearly touch, females will have eyes with a noticeable space between them.
I would assume these flies could be considered pollinators from their habit of nectaring at various flowers and spreading the pollen as they do so.

Look for them right now in your gardens among the flowers. They become quite plentiful during the hottest days in the summer.


  1. Interesting family, I enjoyed watching the one I sent to you.Yours looks like it has more bristles.Are they eating the mint or what is the draw.I didn't realize they drank the nectar, I had a group of another species on my coral bells, they were thick.

  2. I agree they are interesting flies...I like watching them too. I think the photos you sent me of your fly are like the fly in the second photo here. I had two different species going crazy after the nectar.

  3. I live in texas and belive i saw one of these flies recently for the first time in my life it had a black bristely body and a white head and was about half an inch long i found it in my bedroom and was scared to death could this be the same insect ?

  4. Charlotte it sounds like that is exactly what you found. It is harmless, in fact they are beneficial. As larvae they feed on insects such as moths. As adults they exclusively nectar at flowers.

  5. I've lived in Texas 28 years. I had one in my car once- slightly injured myself exiting the vehicle. No one believed my tale of the inch-long fly.
    Many years later, after I had convinced myself I had imagined the prehistoric size, I discovered an even bigger one making an ungodly racket around a fluorescent light in the garage. Rescuing it (?) involved a fish tank net and suppressed screams.

  6. Kept buzzing me and resting on my straw hat it looked like small black bumble bee