''Sesommata platysaris'' is a

moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...

of the family Palaephatidae. It was described by

Edward Meyrick Edward Meyrick (25 November 1854 – 31 March 1938) was an English schoolmaster and amateur entomologist. He was an expert on microlepidoptera and some consider him one of the founders of modern microlepidoptera systematics. Life and work Ed ...

in 1931.Davis, Donald R
"A New Family of Monotrysian moths from austral South America (Lepidoptera: Palaephatidae), with a Phylogenetic Review of the Monotrysia"
It is found in the lake region in

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

, including Lácar Lake and especially

Nahuel Huapi Lake Nahuel Huapi Lake () is an Andean lake in the lake region of northern Patagonia between the provinces of Río Negro and Neuquén, in Argentina. The lake has a northwest-southeast elongated shape and complex geography with several branches, pe ...

. The length of the forewings is 4.8-6.2 mm for males and 5.4-5.6 mm for females. Adult males have dark fuscous to black wings, with a relatively large, rounded mass of broad sex scales. The forewings of the females are smooth and sometimes have a few scattered white scales. Adults are on wing from November to January in one generation per year.

References

Moths described in 1931 Palaephatidae {{Palaephatoidea-stub