Description: 8-13 mm. Similar species are Hemmiargus ceraunus and Cyclargus ammon. Males are blue above with a pair of blue spots on the dorsal hindwing. Females are blue with black boarders and a red and black eyespot on the hind wing. Ventrally, sexes are similar. They have a gray base with white markings as well as 4 black spots on the ventral side that differentiate it from other blues. Ammon has only 3 of these black spots. The Miami blue also has two black spots on the hindwind one of which is capped with red.

 

Habitat and Distribution: The Miami blue used to be common in Dade and Monroe Counties but in the 70's and 80's saw a huge decline. Bahia Honda Key was the last stronghold of this species in the Keys but now it is believed to only reside on barrier islands. 

 

Host Plant: Historically Balloonvine (Cardiospermum corindum) and (Cardiospermum halicacubum). The population on Bahia Hinda Key was strictly eating Nickerbean (.........)

 

Natural History: This species was very common throughout its range anywhere its host plant lived. It was concidered by many collectors to be a nuisance as they would be looking for Chlorostrymon simaethis larvae in balloon vine pods, they would take home what they believed to be hairstreak larvae only to find out that they were Miami Blues. They saw a rapid dscline in the 70's and 80's and were believed to be extinct or at least extirpated from Florida as of the mid 90's until a colony was discovered in 2002 on Bahia Honda Key where it feeds strictly on gray nickerbean. There were efforts to recolonize formerly populated areas on the mainland but none of those colonies established. Now this butterfly can only be seen in several barrier islands of the Keys and is listed as an endangered species by the State of Florida.