Species novaehispaniae Calvert, 1907 [Enallagma]
Syn Enallagma ypsilon Needham, 1942
This species has a dark head with large oval blue postocular spots that are usually not confluent with the occipital bar. The pterothorax largely pale blue with thin black middorsal and humeral stripes. Both of these stripes are generally wider in the female. The abdomen is largely black dorsally, with blue or violet on the basal and apical segments. Segments 8-9, in the male are pale dorsally with a black ventrolateral stripe. There is also a black apical band visible on segment 8. Segment 10 is black. The cerci are long and strongly forked; clearly visible in the hand. Segment 8 in the female is pale with an irregular black apical stripe. Segments 9-10 are black with a large pale apical lateral spot.
Total length: 29-35 mm; abdomen: 23-29 mm; hindwing: 17-19 mm.
Female Skimming Bluet (E. geminatum ) is similar, but abdominal segment 9 is all black in that species. Claw-tipped Bluet (E. semicirculare ) is generally similar but larger and overall more violet in color. The middorsal thoracic and humeral stripe in Dusky Dancer (Argia translata ) are broader, much broader than the antehumeral area and the distal abdominal segments in the female are longitudinally striped.
Clear streams and rivers with a strong current.
This is a tropical species, as its name implies, whose northern range includes the central and southern parts of Texas. Though it can be the most common damselfly at certain streams, the larva remains undescribed and nothing has been reported on its biology.
Texas south through Mexico to Peru and Argentina.