Subject: Black Moth?
Location: Bay Area, California
August 20, 2015 10:57 am
Just found this moth like creature in my garden this morning (8/19/15) in Fremont, California, zip code 94536. What is it?
Signature: Elizabeth Cerutti

Female Western Horse Fly

Female Western Horse Fly

Wow Elizabeth,
This is one gorgeous image of a female Western Horse Fly,
Tabanus punctifer, who can be easily distinguished from her sexually dimorphic mate by the spacing between her eyes and the color and pattern of the white hair on her thorax.  According to BugGuide:
“From Middlekauff & Lane:
Female: A large, dark-colored horse fly. Easily recognized by the following characteristics: mesonotum covered with creamy hair over a dark reddish background: remainder of thorax dark brown, with concolorous hair: wings brown, paler posteriorly, the cross-veins and furcation distinctly margined with brown; legs black, except basal third of fore tibiae, which are creamy white with long white hair; abdomen black.
Male: Color as in female except that the white of the mesothorax is confined to a lateral band and the outer margin of the scutellum.”
The pastel colors of the succulent plant act as a perfect background for this striking fly.  Female Horse Flies are blood suckers that feed on warm blooded animals, and many species are not at all opposed to sucking human blood.

Wow, thanks for such a quick, complete and descriptive answer!  I had no idea it was in the fly family, and a dreaded horse fly at that. When I was growing up on Long Island, NY, we used to try and dodge horse flies in the swimming pool in the summer.  They were so smart, they used to hover right above and wait for us to surface for air.  Hell of a welt.  This one today in the garden was easily an inch long.
Thank you, again.
Best regards,

When we were putting together our response for you, we searched our archives for an image of a male Western Horse Fly to no avail.  Should you happen to see one, please take an image and send it to us.  Here is a BugGuide image of a male Western Horse Fly.

Location: Bay Area, California

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