Iolaus diametra

{{Short description|Species of butterfly}}

{{Speciesbox

| image = SeitzFaunaAfricanaXIIITaf69.JPG

| image_caption = Seitz Fauna Africana Taf69 (line a)

| status = LC

| status_system = IUCN3.1

| status_ref = {{cite iucn |author=Westrip, J.R.S. |date=2021 |title=Iolaus diametra |volume=2021 |page=e.T62099A165245718 |doi=10.2305/IUCN.UK.2021-2.RLTS.T62099A165245718.en |access-date=18 November 2021}}

| taxon = Iolaus diametra

| authority = (Karsch, 1895)[http://www.nic.funet.fi/pub/sci/bio/life/insecta/lepidoptera/ditrysia/papilionoidea/lycaenidae/theclinae/iolaus/index.html Iolaus] at Markku Savela's Lepidoptera and Some Other Life Forms

| synonyms = *Epamera diametra Karsch, 1895

• Epamera diametra littoralis Congdon & Collins, 1998
• Epamera diametra zanzibarensis Congdon & Collins, 1998

}}

Iolaus diametra, the natal yellow-banded sapphire, is a butterfly of the family Lycaenidae. It is found in Africa, roughly from South Africa to Ethiopia.

The wingspan is 26–28 mm for males and 27–29 mm for females. Adults are on wing from July to December with a peak in October in South Africa. There is one generation per year.{{cite book|last=Woodhall |first=Steve |title=Field Guide to Butterflies of South Africa |year=2005 |location=Cape Town, South Africa |publisher=Struik |isbn=978-1-86872-724-7 }}

The larvae of subspecies I. d. natalica feed on Actinanthella wylliei. Other recorded food plants are Oliverella hildebrandtii and Englerina woodfordioides.{{Cite web |url=http://atbutterflies.com/downloads/lycaenidae_iolaina.doc |title=Afrotropical Butterflies: Lycaenidae - Subtribe Iolaina |access-date=2012-08-28 |archive-date=2014-04-07 |archive-url=https://web.archive.org/web/20140407084404/http://atbutterflies.com/downloads/lycaenidae_iolaina.doc |url-status=dead }}