JMX, SNMP, Java, etc...

Yesterday I was browsing on the Internet when a page banner caught my eye. The banner featured a beautiful picture of four insects. A fly, an ant, a spider and a beautifully colored butterfly. Next to each picture was a checkbox. And the question was:

Which does not belong to the group?

I was hooked. For indeed, which doesn't belong to the group? Having the soul of a poet, I was stricken by the beauty of the colorful butterfly. Surely, such a beautiful, fragile, and colorful insect couldn't possibly belong to the same group as the dull grey-brown nasty beasts pictured on the same page?

The butterfly it is! said I.

But as I was ready to click on the butterfly checkbox, another thought occurred to me. I am a great fan of Woody Allen. Which insect would Woody Allen choose? The ant of course. I am no great philosopher, but philosophy is something I do feel interested in. The ant reminded me of Antz. And there's a great philosophic difference between the ant and the other three insects. The ant is the only one of the four that lives in colony - and which is not free to make an individual life. The ant would die without the colony. Surely such a big philosophic difference would take the ant apart from all the three other species on this page?

The ant it is! said I.

But as I was ready to click on the ant checkbox, I had another idea. Being an IT engineer, I also have a cartesian mind. The spider bothered me. For the spider has eight legs. The spider belongs to a whole different order: the arachnids. The spider was the greatest predator on this page. Surely, cartesianally, the spider is the one that didn't belong with the others. Left alone with the three others, and free to roam from the picture that imprisoned it, the spider would shortly spring on the other three, poison them, tie them, eat them, digest them, until only the spider would remain. Surely this sets the spider far apart from the other three?

The spider it is! said I.

But once again, I hesitated. What was the stupid fly doing there? Was I being paranoid? So far the fly was the only one for which I hadn't figured a single reason as to why it wouldn't belong to the group. I had in turn half decided for each of the other three, but not for the fly. Was that what made the fly different from the other three? That it was the only one that couldn't not belong? Wasn't that the greatest difference of all? Wasn't that the expected answer?

Should I choose the stupid fly? I wondered...

Well I must admit, I am still puzzled. Maybe this is in fact another instance of a Wicked Problem.
What would have been your take?