European House Spider, Cluster Fly

2007 March 10

Come in to my parlor
said the spider

to the fly

This is much better. The built-in macro mode on the Canon Powershot A95 seems to work quite well, and actually having some optical zoom means that I don’t have to get so close that the camera shades the arthropod I’m trying to photograph. The fly is still not exactly a thing of beauty, but it is certainly much sharper than the one I took on the window with the other camera.

Anyway, the fly is obviously a fly, hard to say what species exactly because all the members of the family Muscidae look pretty similar. I don’t think it is Musca domestica, at any rate, it doesn’t have the right pattern of body striping and the wings overlap too much. Whatever species this is, it’s the one that gets into our woodwork every winter and hibernates in great numbers, and get all over the house whenever we get a warm spell. It is most likely a cluster fly, genus Pollenia, I doubt it can be narrowed down much more than that without a microscope and maybe some dissection. The flies in our house fit all the descriptions of cluster flies I can find, though: slow-moving, drawn to the sunny windows, hibernate in houses in great numbers, wings overlap significantly when at rest, and no really distinctive color or striping patterns. Their maggots parasitize earthworms, and the adults are harmless but annoying.

I’m pretty sure the spider is a juvenile European House Spider, Tegenaria domestica[1]. We have a lot of these, this one was hiding under a tool box in the basement. Like a lot of people, I used to call these “wolf spiders”, but wolf spiders are actually outdoor-living spiders with relatively large eyes that are rarely found in houses. An observant person will note that this particular spider only appears to have seven legs. That’s because it’s eighth leg evidently fell off when I moved the toolbox.
Eighth leg of European house spider
Fragile little guys, aren’t they?

[1] Note added almost two years later: I now have a much bigger writeup about European house spiders, with better pictures

[2] And also a more extensive writeup on the Cluster Flies.

3 Responses
  1. Leslie permalink
    September 1, 2013

    I have seen plenty of these, or look like the one in the photo, big ones, and jumping babies. They seem to be hard to kill and have a light under side, or at least the tail end. I am so afraid of spiders, never got bit by one as I know of, but have always been terrified of spiders. I am afraid that this one is deadly or there about, can you send me a picture of a wolf spider, jumping one at that?
    Thank You,

  2. September 4, 2013

    Leslie: If you click on this link:

    you’ll see a list of all my wolf spider postings, with plenty of pictures. And this link:

    is a list of all of my jumping spider pictures, which are quite different from the wolf spiders. None of these are venomous enough to cause any harm, and even with all of my handling of spiders, I have never gotten one to bite me. Never.

  3. Leslie permalink
    September 4, 2013

    Hi, Thank You for the information, I believe I have the Northern California Wolf Spider, no matter what, I still don’t like them, they are scary and can run so fast, but are they that hard to kill? I found they are. Can you give me more information on how to keep them from coming into my house, I have a wall plug in for all kinds of pest’s and if seemed to have been working up until the other day when I saw that nasty critter, they just scare me.
    Thank You,

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