what´s with the names?
vittata versus vittatum & vincta versus vinctum
I usually see the -a version
Is this a similar thing as with Oulema melanopus
doesn´t make much sense from the little latin I´ve learned in school

The correct spelling of species names depends on grammatic gender of the generic name - which is a science of its own. Most generic names are partly, or completely, latinized Greek (for sure all with a "y", "ph", "ch" in it), and in Greek, -a does not indicate maculine or neuter/plural, as in Latin.

species names that are regular flexed adjectives end in -us(m), -a(f), -um(n), not so do species names in the nominative and genetive case, and adjectives of different flexation groups (those ending in -is).

For the changes in Acalymma, I followed the google hits (more, and more of them from not-applied sources for -um, including ITIS) - but you are right, I don´t know for sure what is correct.

Oulema melanopus is a funny case. Lema clearly is feminine (so has to be Oulema, consquently). I guess, that in this case, the "foot" (masculine) in the name takes the dominant role.

I think others (at least Jim Mclarrin and Tom Murray) have agreed to follow the list of nomina arctica:
http://www.nearctica.com/nomina/beetle/colchrys.htm
But probably the -um version will prove the correct one in the end, but it´s listed as -a

I would agree to follow ITIS nomenclature but seldom think to check names there. Over half of my species IDs are supplied by others anyway.

N.N. often gives thwe species names in the original spelling - means, in the correct spelling for the genus in which originally described. In case of transfer, splitting of genera, this often is incorrect today.

you´r probably right, but there is probably no list which has it all correct. The common species in Acalymma give 360 hits for vittata and 226 for vittatum. So it´s a mess anyway. Maybe the ITIS list is better?? Don´t know that one. It would just be better if everybody on bugguide was using the same list/names I think.
Maybe we should discuss this in a forum rather than here....or just leave it

Boris; great new site. Let´s hope european musea will follow this example so I can finally try to get some peruvian Chrysomelids with firm id´s. Concerning Acalymma. This one seems very like the (Diabrotica) vincta type. Anyway to find out if this species is known from Georgia? I think it will be ok to make a species page for now. The new Acalymma from Canada seems like typical common vittata to me, but than I don´t know gouldii
cheers,

Rob

Forgot to add thumbnails.
On the thumbnail, note the white outline on the thorax.

These are two different species looking very similar to each other to send out the same signal to birds, lizards and other possible enemies they might have, saying as much as ´I am not edible´. Actually they are not related although they are both in the family of leafbeetles. The beetle on the right is a fleabeetle (Alticini) which have the hindlegs adapted for jumping. The species is probably in the genus Disonycha sp. The other is a species of Acalymma in Skeletonizing Leafbeetles (Galerucinae). There are also some beetles from other families and even some bugs with a similar colourpattern.