I’ve spent most of my time this past week going through a veritable mountain of Evaniidae from all corners of the world and sorting them – to the best of my little mind’s ability – to genus level.

I’m finding that certain geographic regions are proving more difficult than others. Australasia/Malesia and continental southern Africa have proven to be the most challenging regions. This is probably due to high diversity of these areas combined with the “squishiness” of the key I’m using – for example: if it looks like a Micrevania, but it’s from South Africa, not Madagascar, is it still Micrevania?

It’s been quite the mental workout so far, but I’m finding that the more I toy with these specimens the more absorbed I become with the task of figuring these little beasties out. With every new wasp I learn a little bit more and become a little more comfortable with the taxonomy of this family.

There is, however, one question that only seems to nag me worse and worse as my understanding of Evaniidae grows. I feel it is a question that comes to live with most (if not all) taxonomists at some point in their career. Namely: what really is this taxonomic level we call genus?

This question, in turn, opens up a thousand more to be asked:

What makes one species a member of one genus, but another species a member of another genus?

Where do we draw lines to delimit genera?

Is a genus ranking just a place to stick species into some made up hierarchy so that we can toss names around easier, or is it intended to be a useful grouping to delimit some number of species into distinct chunks that describe actual relationships? If so, how closely do these species need to be related?

Can a genus contain only one species? Can it contain a billion? If so, did designating a genus actually help us to understand the world a bit better?

Et cetera, ad infinitum, ad nauseum…

I don’t have answers to these questions yet. I don’t think anyone has answers to these questions yet. We have come up with numerous species concepts, each with their own set of failings, but it seems that no one has come up with a well structured genus concept. A monophyletic grouping of species seems to be the best joint consensus taxonomists can come to and any further criteria for classification appears to be largely in the hands of each taxon’s specialist. This muckiness of what makes something a genus has yielded a mottled patchwork of groups that are variably more or less useful and meaningful. To me, this is problematic.

Jumping off on a somewhat lighter, less philosophical note, a few observations from our recent trip to Bear Meadows:

Wading around in the stream was great fun, and I managed to net a number of Odonates while sloshing about up to my armpits in bog water. It should be mentioned that there are some rather deep spots in there. There were a couple times where I took a step and my foot never reached the bottom- use caution or bring a towel.

I didn’t get much in terms of aquatic matures – lots of pupae and larvae but not much else.

I’d also like to report on the first pselaphine of my stay here in Pennsylvania: Thesium cavifrons.

The genus Thesium is a largely neotropical group with two species found in the extreme southwest U.S. and one species (T. cavifrons) found throughout the eastern US. I must also report that, despite all my scratching around at rocks and logs, this specimen was taken from (of all places) a yellow pan trap.

Unfortunately, I managed to cut the poor little fellow in half while trying to get a better photo of it, so here’s a picture of Oxyporus quinquemaculatus, another interesting catch from the yellow pan traps: