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Showing posts from December, 2014

Difficulty identifying Anyphaena dixiana

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Usually when I come across a spider, I can tell which family of spiders it belongs to, but this spider baffled me. I found a female under a dog bed on my patio on November 23, 2014, in Austin Texas. Three days later I found a similar-looking male spider, and again I couldn't be sure of the family.


The female is on the left, the male on the right. These photos are not proportionally scaled: the female has a body length of 4.5mm and the male 4mm. We don't include the legs.

These two spiders have the general body shape and color pattern of a wolf spider (lycosidae), but they don't have the eyes of a wolf spider. Often a spider that looks like a wolf spider but isn't might be a funnel spider (agelenidae), but these eyes also were not a match for agelenidae. It is hard to see in these photos, but these spiders' eyes are in two rows of four, with all eyes about the same size. Funnel spiders have eyes in three rows, except for Tegenaria, which these definitely are not.

The…

Problem-Solving Strategies

Here is a list of problem-solving strategies. Most of these strategies arose from reflection on how I develop software design specifications. This is an evolving document.

Identify and attack tangentially related problems. This often sheds light on or even resolves the original problem, even if the process happens to reveal more problems.Create solutions gradually by iterative refinement. The best solutions are evolved. Solve select problems, leaving others unsolved. Gradually throw more solutions into the mix. Don't expect solutions to grow by accrual, as periodic complete transformations may be necessary. Each new iteration still benefits by being derived from preceding solutions.Find and depict specific examples of the problem. Articulate the problem separately for each example to find a common articulation or to learn the problem's component pieces.Find the right questions to ask -- about the nature of the problem and what is desired in the solution. Asking questions about …

The True King of the Sky

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The robber fly is usually considered to be the top aerial predator of the bug world. These photos may dethrone the robber fly and establish the spider as true king of the sky.

This past summer, I visited an Argiope aurantia (aka "Black and Yellow Garden Spider") in my front yard day after day to see what she was up to. She had made her web below some cables that string to my house. I often saw a robber fly monitor the sky from the bottom cable. I thought it was a cool sight and took this photo on August 7th, 2014.


Three days later, on August 10th, I found that my spider had caught a robber fly. This isn't a great photo, but it shows the spider's web near the cables on which the robber fly would perch. She is feeding on a robber fly in this photo.


This close up makes it clear that her prey is a robber fly. Out of curiosity, I kept looking for a robber fly on the cable for days afterward but never saw one there again. I suspect that my first photo is of the very robber…