Re: [beemonitoring] Coelioxys octodentata vs C. sayi - separation of males
- Hi Sam:
Yes, this is a difficult ID.
I've been found that the ocellar character (octodentata with ocelli closer
together relative to long vertex) SEEMS TO work for me much (perhaps not
all) of the time, when considering size (sayi often smaller) and color
(sayi usually with darker legs) too, but perhaps I'm fooling myself. We
have many det. (by Baker and by me) specimens of both species if you wish
to check them sometime.
There may be a different in puntures on the vertex as well at least on
I recall being unhappy with certain Baker dets. of this pair when I was at
Cornell, but perhaps this merely reflected my inexperience at that time.
> Greetings Everyone:--
> I think the new bee monitoring list is ready to use. If you know of
> anyone who would like to join you can email me their address and I
> will sign them up.
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> Below is something that has frustrated me for a long while. After
> looking at many specimens and sorting through quite a number of
> misdetermined specimens I have come up with the following guide for
> these common species. I would be interested in any comments ...
> C. octodentata vs C. sayi - combination of characters - a difficult
> pair to separate, most collections have numerous misidentifications
> C. octodentata - Primary character is the latitudinal groove that
> transverses T2 and especially T3, this groove is continuous across the
> segments, look particularly in the center of these segments, here it
> maintains a depth about the same as that on the sides and the pits in
> the bottom of the groove are continous, touching one another without a
> break and always touching - In addition to the character there is a
> PROPENSITY for the following characters to also occur, but beware,
> numerous exceptions occur femur orange, pits on center of T5 touching,
> some pits on center of S2 touching, distance between lateral ocelli
> less than distance from lateral ocelli to back of head we have seen no
> examples where the distance is more
> C. sayi - Primary character is the latitudinal groove that transverses
> T2 and especially T3, one can imagine that this groove is continuous
> across the segments, but look in the center of these segments, here,
> particularly on T3 it becomes very shallow, more like a depression
> than a groove, in contrast with its depth on the sides, the pits in
> the bottom of the groove are not continuous in the center, there is a
> break in the center where the pits no longer touch one another and
> some small gaps in the line of pits occur - In addition to this
> character there is a PROPENSITY for the following characters to also
> occur, but beware, numerous exceptions occur femur orange to part
> orange, to completely dark, pits on center of T5 usually not touching,
> pits on center of S2 usually not touching, distance between lateral
> ocelli varies and can be less than, equal to or more than the distance
> from lateral ocelli to back of head
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John S. Ascher, Ph.D.
Bee Database Project Manager
Division of Invertebrate Zoology
American Museum of Natural History
Central Park West @ 79th St.
New York, NY 10024-5192
work phone: 212-496-3447
mobile phone: 917-407-0378