Williamson's Emerald - Somatochlora williamsoni

Moved

Moved from Brush-tipped Emerald.
Thanks Ben.

… tom murray, 14 July, 2010 - 3:11pm

Williamson's Emerald male

Hi Tom. I think this is actually a Williamson's Emerald (Somatochlora williamsoni), not a Brush-tipped (S. walshii). The abdomen is too long (Brush-tipped should be shorter than this), and the cerci are the wrong shape, especially from above. Dorsally, Brush-tipped cerci are wide set at the base and convergent in arcs to the tips, whereas Williamson's are longer and more parallel, with a slight constriction before abruptly converging closer to the apex. Williamson's has hairy tips to the cerci as well, though not as dense as Brush-tipped.

Compare the abdominal proportions to this Doucet shot of Williamson's:

… Ben Coulter, 13 July, 2010 - 9:53pm

Jason

Thanks for the confirmation.

… tom murray, 25 January, 2009 - 8:34pm

looks right to me

Appendages should be distinct.

… Jason Forbes, 25 January, 2009 - 8:22pm