About Onychargia atrocyana Selys, 1865
This is a medium-sized damselfly species, with a velvet-black head and thorax, and brown eyes capped with black. In sub-adult and teneral individuals, the dorsum of the thorax has narrow citron-yellow antehumeral stripes. During this life stage, the sides of the thorax are citron-yellow, marked with a broad oblique black stripe across the postero-lateral suture. All of these markings become obscured by pruinescence in fully adult individuals. The abdomen is black and unmarked in adults; in earlier stages, it has narrow bluish basal rings on segments 3 through 6. Sub-adults have yellow markings on the lateral sides of abdominal segments 1 and 2. Females share the appearance of sub-adult males, including their visible yellow markings. This species breeds in forest ponds and marshes.
