I had a test the past semester where some of the questions picked on the tiniest possible detail of something (also regarding insects). Anyways, I don't think it was truly unfair because to me, anything presented in the class is fair game, unless the professor very clearly says otherwise. The professor for our class was along the lines of that the general concepts we should know already because we went over them so many times, and so we may be a bit more uncertain on the tinier details and that is the better way to determine how much the students know or don't know.

I don't think it's reasonable to say that just because you know 75% of the material you should get roughly 75%. The tests cannot cover all the material because there would be too many questions and not adequate time. Also, some stuff may be more important than others and so those get asked, or smaller details are asked because students who know more can answer those questions and know how those smaller details tie in with other details. At least that's what the professor I mentioned feels and I have to agree with him on it. I don't think though that the entire test should focus only on tiny details because I think tests should have some easier questions just so the students have some fairness in what is covered.

I wouldn't have written the stuff on the test but then again, it varies on what you wrote. If you said the test was unfair and that was it, then it may go unpunished but if you write swear words, cuss out the test, professor and so forth, or go on a long rant, then I think that's not going to be seen very well.