Actual female voucher specimen is

Are you sure? The ventral image of this specimen appears to be male.

Dissected so I'm certain. Is this because of the yellow protrusion from the abdomen, or another morphological feature? There were several such yellow objects (presumably eggs) in the abdomen. Perhaps I have a different individual than the photographed one?

Also, can you elaborate on any external characters useful in separating this species from M. floridana? Thanks!

I actually began a publication on separating these two species a while ago and have been working on it periodically, so hopefully I finish soon and be able to link to it on the info page.

Mantura chrysanthemi has a more heavily convex pronotum and narrower impressions than floridana. chrysanthemi is usually the same uniform dark color while floridana is variable, but in darker specimens of floridana the apex of the elytra is usually paler than the base. The best non-subjective external character I have found to separate the two is the prosternum. In floridana the prosternum is evenly convex while in chrysanthemi it is flattened in the center in an upside-down triangle. Of course this usually works better for physical specimens than photographs. Both the spermatheca and aedeagus are also highly different between the two species, so there should be no difficulty telling them apart by dissection. FYI, in the Field Museum collection there is a specimen of chrysanthemi collected in Indiana, so you may have them in your area as well.

Thanks for the detailed information about species separation as well as the sexing information below. I see now what you mean.

In male flea beetles the 5th (apical) sternite is modified with a central protrusion. See the diagram here for an example of what a male looks like: http://www.sel.barc.usda.gov/Coleoptera/fleabeetles/morp244.htm
In females the apex is evenly rounded without any modifications. The abdominal image in this series appears to have emarginations to either side of the apex, indicating it is a male. This specimen is a female: http://bugguide.net/node/view/928076

I believe I lost this specimen and found another but forgot to update the photos. The full sized image of this one does appear to be male, I posted what I believe to be the female you received here -



Sorry for the confusion.

Thanks John. I'll redirect my voucher comment.

If I had more than one on my desk I could have put the wrong one in the vial. I try to be careful and I apologize if that happened. This seems to be a fairly common beetle around here.