Attached is a dichotomous key to the
eastern male forms of bidentate Nomada.
I have been working on this particular
group and the associated females for quite a long time. I have seen
many of the holotypes, many identified specimens, and several nice collections
from several of you (thank you very much!). I have sorted, resorted,
scored, rescored, used cluster analysis, read the literature still feel
that things are still not settled. However, some patterns have emerged
and I believe that I am near the end of what I can do through direct measurement
and observation. There is an opportunity to do some molecular
work on this group in the future and I hope that will help sort things
out a bit further.
The guide below, with the exception
of well defined Nomada maculata, uses the term Form and a series
of letters to denote different groupings. The reason for this is
that there are a number of problems with the names of the holotypes and
their associations with names in collections, there are some likely synonyms,
and there appears to be some major mismatches between Robertson's types
and what has been the common naming practice. This and the problem
of my lack of clarity in species boundaries has led me to believe that
for the time being it would be better to leave things as a set of numbered
forms that can be later associated with names. In the mean time,
people doing ecological work have (hopefully) a clearer and more consistent
means of splitting their specimens.
Any comments are very welcome as are
large collections of this group from one locality that could inspect.
P.S. I will send out a key to the more
difficult females next then some general short accounts.
Sam Droege Sam_Droege@...
w 301-497-5840 h 301-390-7759 fax 301-497-5624
USGS Patuxent Wildlife Research Center
BARC-EAST, BLDG 308, RM 124 10300 Balt. Ave., Beltsville, MD 20705
Out beyond ideas of wrongdoing and rightdoing,
there is a field. I'll meet you there.
When the soul lies down in that grass,
the world is too full to talk about.
Ideas,language,even the phrase " each other"
doesn't make any sense