Prosotas gracilis

{{Short description|Species of butterfly}}

{{Speciesbox

| image = Prosotas gracilis 246679652.jpg

| image_caption = Underside

| image2 = Prosotas gracilis 246552232.jpg

| image2_caption = Upperside

| taxon = Prosotas gracilis

| authority = (Röber, 1886)Röber, J., 1886. Neue Tagschmetterlinge der Indo-Austalischen Fauna. Deutsche entomologische Zeitschrift Iris. 1(3):45-72, 4 pls

| synonyms = *Plebeius gracilis Röber, 1886

• Nacaduba gerydomaculata Rothschild, 1915
• Prosotas gracilis bonthainica Toxopeus (nomen nudum)
• Lycaena donina Snellen, 1901
• Nacaduba ni de Nicéville, 1902{{cite journal|last1=de Nicéville|first1=Lionel|authorlink1=Lionel de Nicéville|editor1-last=Phipson|editor1-first=H. M.|editor2-last=Millard|editor2-first=W. S.|title=On new and little-known Butterflies, mostly from the Oriental region|journal=The Journal of the Bombay Natural History Society|date=24 May 1902|volume=14|issue=2|pages=247–248|url=https://biodiversitylibrary.org/page/30157890|accessdate=19 March 2018|language=English|format=PDF|issn=0006-6982|oclc=863086885}}
• Nacaduba basiatrata Strand, 1910
• Nacaduba saturatior Rothschild, 1915

}}

Prosotas gracilis or The Dark-based Lineblue is a butterfly in the family Lycaenidae. It was described by Julius Röber in 1886. It is found in the Indomalayan realm.Seitz, A., 1912-1927. Die Indo-Australien Tagfalter. Theclinae, Poritiinae, Hesperiidae. Grossschmetterlinge Erde 9: 799-1107, pls. 138-175.