Ophion confusus

I initially tried using Gavin Broad's key to nocturnal Ichneumonidae to identify this, but struggled with a choice between costatus and mocsaryi. I couldn't really tell if the depth and definition of the groove bordering the posterior side of hind ocellus was a better match for one or the other, the flagellomere count was in the overlap zone (57). The shape of the epicnemial carina was a better match for mocsaryi and I didn't think the wings had any smoky or yellowish suffusion, though at some angles it looked like they might have. Those two characters seemed to point to mocsaryi but the last character in the couplet, the shape of the propodeal spiracle, seemed to match costatus better.

At this point I turned to the review of the Swedish Ophion by Johansson and Cederberg and also ended up with a choice between mocsaryi and another species, but this time the other species was confusus, a species first descibed in this paper and therefore missing from Broad's key which I think predates it. Most characters here pointed to confusus: the occipital carina was evenly rounded and the longitudinal carinae delimiting area superomedia were missing anteriorly, or at least very weak and hard to see. The anterior transverse carina was only darkened and obvious centrally, but did continue laterally, albeit weakly and undarkened (this was more obvious on the right side than the left). Judging the differences in the face was tricky but the punctures were pretty dense and deep. In the absence of specimens to compare I'm not quite sure what the shagreened appearance should look like - mine had some net-like microsculpture between the punctures, but I'm not sure that's what it refers to. Likewise the dorsal shine and coarseness is hard to call without comparative material.

Unfortunately one character pointed to mocsaryi rather than confusus: the length of the basal flagellomeres. The diagram in the paper shows nicely rectangular flagellomeres but the reality is not so rectangular as the ends are not perpendicular to the sides, especially if viewed from below (which was easiest for me) or from above (I'm never quite sure, but I think this may be standard for some taxa?). So if the flagellomere is parallelogram-shaped, is the length the length along the midline, or an edge (which would be almost the same) or the total length so the distance along an axis parallel to the antennae from the level of the farthest point of the paralellogram to the nearest point - which would be longer. Either way, viewed from above or below I struggled to find a way of measuring it so the ratio was less than 1.7. I took a lot of measurements of the second and third flagellomeres at various orientations - all over 1.6 times longer than wide.

The key emphasises that a combination of characters must be used as no single characters are diagnostic. It is also, I think, a male and the key says it works best for females, the shape of the flagellomeres being one of the characters that may be less distinct in males. So on balance I have identified it as confusus. However, I will retain the specimen so that it may be reviewed again in the event that I ever find more examples of the two species.

An update: in May 2024 I found what I believe to be Ophion mocsaryi and noted a number of differences between that specimen and this one which significantly increase my confidence that this one was correctly identified as confusus. Regarding the character that bothered me most, the proportions of the basal flagellomeres, these were clearly longer on the mocsaryi. See my Ophion mocsaryi page for a more detailed description of the differences.

Ophion confusus showing antennae, first flagellomere, second & third flagellomeres, mandibles, face (clypeus bottom left and antennae top right), head from above, ocular-ocellar region (2 angles), forewing, epicnemial carina (3 angles), propodeal spiracle, scutellum, propodeum (2 general views, 2 focusing on the area superomedia and 1 on the anterior transverse carina), hind femur and first tergite, Wendling Beck Environment Project (Norfolk, UK), 11th June 2023