Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Clickable Guide
Moths Butterflies Flies Caterpillars Flies Dragonflies Flies Mantids Cockroaches Bees and Wasps Walkingsticks Earwigs Ants Termites Hoppers and Kin Hoppers and Kin Beetles True Bugs Fleas Grasshoppers and Kin Ticks Spiders Scorpions Centipedes Millipedes

Upcoming Events

Information, insects and people from the 2019 BugGuide Gathering in Louisiana, July 25-27

Discussion, insects and people from the 2018 gathering in Virginia, July 27-29

Photos of insects and people from the 2015 gathering in Wisconsin, July 10-12

Photos of insects and people from the 2014 gathering in Virginia, June 4-7.

Photos of insects and people from the 2013 gathering in Arizona, July 25-28

Photos of insects and people from the 2012 gathering in Alabama

Photos of insects and people from the 2011 gathering in Iowa

Deer Louse Fly

Deer Louse Fly
Sweeney Ridge, Golden Gate National Recreation Area, San Mateo County, California, USA
September 14, 2007
I've been seeing these occasionally for years and wondering what in the world they were. Typically they land on your arm as you're walking down a trail in the afternoon. They're somewhat flattened, with stubby legs, and at first sight they look like some strange "winged tick", though one quickly notices they're six-legged.

At last I think I figured out what they are...Deer Louse Flies. From what I've read, we have two species in California: Lipoptena depressa and Neolipoptena ferrisi. According to Powell & Hogue(1), L. depressa exhibits "V-shaped lines on the upper surface of abdomen" (see this image), whereas Neolipoptena ferrisi does not. Unfortunately, the top of the abdomen isn't visible here (and I didn't know to look for that character when I saw this guy).

Here's a quote with some natural history info on these strange dipterans, from "Insects of the Los Angeles Basin" by Charles Hogue (2):

"Occasionally, a person hiking or working in mountainous areas will notice a small (1/8", or 3 mm, long) flattened brown fly that has landed on his skin or clothing. Looking much like a winged tick, the fly clings tenaciously or crawls sluggishly for a moment before flying away. This is one of the two common local species of Deer Louse Flies (Neolipoptena ferrisi or Lipoptena depressa), which normally live as ectoparasites on deer. ... Upon successfully finding a deer, it immediately crawls through the hair to the skin and begins to suck blood. Here it remains as a permanent parasite, soon losing its wings through wear. ... All Louse Flies are blood suckers, although none feeds regularly on humans. They may transmit disease between wild animals but do not to and between people."

Images of this individual: tag all
Deer Louse Fly Deer Louse Fly

Moved from Louse Flies.

Interesting. Thanks for the link and post.
I must confess that ticks freak me out like no insect could. One of these buggers landed on me, causing a few anxious moments before I counted legs. Until now, I had no idea what the culprit was.

Glad to Solve the Mystery
It was tricky, because the lack of (visible) antennae and unclear wing venation in the photo made me doubt it was a Dipteran. Eventually figured it out through lots of book and web searching.

Moved from Lipoptena, because there's a possibility it may be Neolipoptena ferrisi...though my investigations point to L. depressa as more likely.

Comment viewing options
Select your preferred way to display the comments and click 'Save settings' to activate your changes.