United States and Mexico
Description: Males: One of two large blue drancers in North America that have S7 mostly blue. Eyes blue. With small black medial spots at base of labrum. Thorax with wide median and humeral stripes, latter forkes with outer fork much wider than inner. S2 with complete dorsolateral black stripe, expanding at distal, their ends not touching dorsally. Incomplete rings on S3-4, complete rings on S5-7; S8-10 completely blue.
Females: Eyes dark brown above, pale greenish to tan below. Entirey brown except S8-10 or S9-10 dull blue. Thoracic stripes as in male, lower sides of thorax may be bluish tinged, but brigth andromorph not seen. S2-6 with complete dorsolateral stripes or S3-6 fused with apical rings; S7 all black; S8-9 with paired basal spots.
Size: Total length: 35-43 mm; abdomen: 27-35 mm; hindwing: 22-28 mm.
Similar Species: Males are easily separable from Tarascan and Sabino by the shape of the upper branch of the paraproct. In Pima, this branch is a narrow, linear or curvilinear digit-shaped structure, but in the other two species, it is a broadly based triangle. The epiproct of Sabino and Tarascan is distinctly narrower than the transverse width of each torus, but in Pima, the epiproct is large, swollen, and is about as wide as the transverse width of one torus. Tarascan very similar but with S/ black. Sierra Madre very similar but sufficiently larger that size alone should distinguish species and unforked humeral stripe. Females of Pima are separable from Sabino and Tarascan by the shape of the mesostigmal lobes. They are large, broad distally, and meet the lateral arm of the middorsal thoracic carina at an acute angle. These lobes in Sabino and Tarascan meet the lateral arm of the middorsal thoracic carina at an obtuse angle.
Habitat: Is a stream species. Often rocky streams with moderate current, usually in woodland or forest.
Natural History: As with other species of Argia, found in the largely arid areas of the southwestern United States, abundance can vary from year to year, presumably due to the unpredictable nature of summer rains. Adults usually tandem over small riffles. Pairs oviposit in riffles, in rootlets of woody streamside vegetation.
Distribution: Arizona; Mexico: Sonora and Chihuahua.
Source:
Garrison, R. W. 1994. A synopsis of the genus Argia of the United States with keys and descriptions of new species, Argia sabino, A. leonorae, and A. pima (Odonata: Coenagrionidae). Transactions of the American Entomological Society 120(4): 287–368.
Paulson, D. 2009. Dragonflies and Damselflies of the West. Princeton University Press. 536 pp.
Edited by Juan Cruzado (12/31/2016)
