Description: Males: Eyes black above blue narrow. Thorax blue with rather narrow median stripe and narrow, unforked humeral stripe. Abdomen blue, dark rings at rear of S3-6 with points extending forward on either side; almost all of S7 black, S8-10 blue bordered by black at lower edge. Some with black rings more extensive, S6 may mostly black. When in tandem, color of thorax shifts from blue to dull purple.
Female: Eyes brown dark stripesof male often somewhat obscured by brownish. Abdomen mostly dull blue, middle segments with dark brown posterior ring and stripe extending forward on either side almost to front of segments; thus, prominently striped. S7-9 with dark dorsolateral stripes, extending full or not quite full length of S8, only two-thirds length of S9, but sides of segments completely striped to S9; S10 enterely blue (Paulson, 2009).
Size: Total length: 33-40 mm; hindwing: 20-25 mm.
Similar Species: Tarascan is the same size but it's brighter blue, width thoracic stripes, humeral forked and simple black rings, Harkness's rings with with points on either side and often more black. Sabino more purplish-blue and has widely forked humeral stripe. Aztec and California both smaller with forked humeral stripe. Pima and Sierra Madre slightly larger, with mostly blue S7.
Habitat: Fair-sized rivers with moderate current.
Natural History: Males perch on vegetation or rocks, usually at riffles. Ovipositing pairs colect in shallow riffles with abundant rootlets.
Distribution: This species was considered endemic of Western Mexico, but was registered in Arizona.
Source:
Paulson, D. 2009. Dragonflies and Damselflies of the West. Princeton University Press. 536 pp.
Edited by Juan Cruzado (12/30/2016)
