Above is a collaged reproduction (from the fifth and sixth pages of the PDF for Townes
(1)) of the wing diagrams for
Auplopus architectus architectus (
Plate 2, Fig. 30) and
Auplopus nigrellus (
Plate 1, Fig. 11). I've annotated the figures indicating where I
think the 2nd and 3rd segments of the cubital veins are, and also adding color coding referred to below.
In couplet 10 of the key to species for (female)
Auplopus (
pg. 147 of
(1)) Townes states that the ratio of lengths of the 2nd to 3rd segments of the cubital vein are "about .95" for
architectus vs. "about .85" for
nigrellus.
I have two main difficulties with this...
1) I'm not exactly sure which parts of the cubitus vein are being referred to as the "second segment" and "third segment" here. In Fig. 1A (on pg 7 of
(1)), the cubitus is indicated as the zig-zag vein along the posterior edge of the cubital cells (= "submarginal cells" of many other authors). At first, I presumed the "second cubital segment" was the portion of the cubital vein posterior to the 2nd cubital cell (colored red and yellow in the image above), and similarly for the third cubital segment (colored blue and green above). But each of those segments is met from below by the 1st, and respectively 2nd, recurrent vein...and thus themselves consist of two segments. So perhaps the "2nd cubital segment" is what I've colored
red above, and the "3rd cubital segment" is what I've colored
yellow?
2) Either way one interprets "2nd and 3rd cubital segment", the ratios of .95 and .85 given by Townes for
architectus and
nigrellus, respectively, don't jibe with those appearing in his figures for those taxa. Using Photoshop to carefully measure the ratio in the figures above, I get:
.72 = ratio of (red + yellow)/(blue + green) for
architectus;
.77 = ratio of (red + yellow)/(blue + green) for
nigrellus
and
1.2 = ratio of red/yellow for
architectus;
.75 = ratio of red/yellow for
nigrellus
So neither of the two interpretation of "2nd/3rd cubital segment" gives results in accord with the values of .95 and .85 presented in 'couplet 10' of the key. In fact, the descrepancies between the values from the figures and those of the key are substantially more than the descrepancies the key asks to discriminate between! Moreover, these quantities are relatively difficult to measure with enough accuracy to confidently avoid the seepage of error greater than the discrepancy between .95 and .85, so the practical value of this character seems questionable to me.
Nevertheless, just for fun (and completeness) here are the ratios I got for my specimen:
.79 = ratio of (red + yellow)/(blue + green);
1.1 = ratio of "red/yellow"
For what it's worth, the first ratio (which I think is more likely the one intended by Townes), as measured from the specimen, matches better with the figure for
nigrellus; while the second ratio for the specimen matches better with the ratio in the figure for
architectus. And both ratios are relatively far from either of the candidate values given in 'couplet 10' of Townes' key! (Not very reassuring as to the consistency or utility of this character for discriminating these species! ;-)
